Toyota Prius

Toyota Prius

Manufacturer	Toyota Motor Corporation
Production	1997–present
Class	Hybrid car
Layout	FF layout

The Toyota Prius (pronounced /ˈpriːəs/) is a full hybrid electric mid-size car developed and manufactured by the Toyota Motor Corporation. The Prius is the most fuel efficient gasoline car currently sold in the U.S. according to the United States Environmental Protection Agency.^[1] The EPA and California Air Resources Board (CARB) also rate the Prius as among the cleanest vehicles sold in the United States based on smog forming and toxic emissions.^[2]

The Prius first went on sale in Japan in 1997, making it the first mass-produced hybrid vehicle. It was subsequently introduced worldwide in 2001. The Prius is sold in more than 40 countries and regions, with its largest markets being those of Japan and North America.^[3] In May 2008, global cumulative Prius sales reached the milestone 1 million vehicle mark,^[4] and by June 2010, the Prius reached worldwide cumulative sales of 1.8 million units.^[5] As the global top seller market, the U.S. made up more than half the Prius sold worldwide, with 814,173 units registered by December 2009.^[6]

Development

1996 Prius prototype.

On January 16, 1992, the Toyota Motor Corporation announced the Earth Charter, a document outlining goals to develop and market low emission vehicles.^[7]

In September 1993 Toyota R&D Executive Vice President Yoshirio Kimbara created G21, a committee to research cars for the 21^st century. On February 1, 1994, the first official meeting of the G21 project team took place. The team determined the goal of G21 is to create a car that is resource and environmentally friendly while retaining the benefits of modern cars.^[7] The development effort was led by Takehisa Yaegashi, who was tasked with building a car that bridged the gap between electric and gasoline powered vehicles.^[8]

1995–1996 (prototype)

In late 1994, the G21 team designed a concept car with a hybrid engine for the 1995 Tokyo Motor Show. The vehicle was named "Prius," the Latin word for "prior" or "before." It was shown on October 27, 1995.^[7] In late 1996, test driving began.^[7]

1997–2001 (model NHW10)

NHW10 (First Generation)

Production	1997–2001
Assembly	Takaoka, later Motomachi, Japan[9]
Class	Compact car
Body style(s)	4-door sedan
Engine(s)	Toyota Hybrid System Gasoline: 1.5 L 1NZ-FXE DOHC I4 13.5:1 compression 43 kW (58 hp) @ 4000 rpm 102 N·m (75 lb·ft) @ 4000 rpm Electric: 288 V motor 30 kW (40 hp) @ 940 rpm 305 N·m (225 lb·ft) @ 0 rpm
Wheelbase	2,550 mm (100.4 in)
Length	4,275 mm (168.3 in)
Width	1,694 mm (66.7 in)
Height	1,491 mm (58.7 in)

The first Prius, model NHW10, went on sale on December 10, 1997.^[10][11] It was available only in Japan, though it has been imported privately to the United Kingdom, Australia, and New Zealand.^[12] Many of these cars are now being exported as second-hand vehicles to New Zealand and other countries.^[13] The common battery failures and other mechanical problems are not supported outside Japan.^[14]

To handle the voltage between the battery and electric motor, the semiconductor core inverter unit was modeled on heavy-duty transistors used by the Shinkansen bullet train.^[8] The first production model NHW10 Toyota Prius was rolled out of Toyota's Takoka factory in Toyota City, Aichi near Nagoya on December 1997, followed by the start of two years of Japan-only sales.^[8]

Side view of the NHW10 Toyota Prius

As uncovered by engineer testing, the NHW10 Prius was vulnerable to reduced performance in hotter climates and at higher altitudes; as a result, early examples featured an instrument-panel indicator warning should the hybrid system be in danger of shutting down. This gauge, designed in the shape of a turtle, was used until 1999.^[8]

The first generation Prius, at its launch, became the world's first mass-produced gasoline-electric hybrid car. Japan sales goals were 12,000 units annually, at a price of US$16,929 per vehicle. Rivals and analysts estimated that the first generation Prius cost as much as US$32,000 to produce, meaning that each NHW10 model was sold at a loss. The vehicle's introduction served as Toyota's launch effort for a new generation of 'green' vehicles aimed at reducing air pollution and increasing fuel efficiency. Toyota initially forecasted that hybrids will account for a third of the world's auto market as early as 2005.^[11]

The NHW10 Prius styling originated from California designers, who were selected over competing designs from other Toyota design studios.^[11]

2001–2003 (model NHW11)

NHW11 (First Generation)

Production	2000–2003
Assembly	Toyota City (Motomachi), Japan[15]
Class	Compact car
Body style(s)	4-door sedan
Engine(s)	Toyota Hybrid System Gasoline: 1.5 L 1NZ-FXE DOHC I4 VVT-i 13.0:1 compression 52 kW (70 hp) @ 4500 rpm 110 N·m (82 lb·ft) @ 4200 rpm Electric: 273.6 V motor 33 kW (44 hp) @ 1040 rpm 350 N·m (258 lb·ft) @ 0 rpm SULEV
Transmission(s)	1-speed planetary gear
Wheelbase	2,550 mm (100.4 in)
Length	4,308 mm (169.6 in)
Width	1,694 mm (66.7 in)
Height	1,463 mm (57.6 in)
Curb weight	1,254.2 kg (2,765 lb)

The 2001–2003 Prius for the United States market was powered by a 1.5 liter Atkinson cycle 4 cylinder^[15] gasoline engine, a permanent magnet AC electric motor, and a 274-volt nickel-metal hydride (Ni-MH) battery pack. The gasoline engine developed 70 hp (52 kW) and 82 ft·lbf (111 N·m) of torque. The electric motor generated a maximum of 44 hp (33 kW) and 258 ft·lbf (350 N·m) of torque.

The NHW11 Prius became more powerful partly to satisfy the higher speeds and longer distances that Americans drive.^[16] Air conditioning was standard equipment.^[17]

Interior.

The vehicle was the second mass-produced hybrid on the American market, after the two-seat Honda Insight.^[18] While the larger Prius could seat five, its battery pack restricted cargo space. The vehicle interior featured a dash-mounted shift lever, and a small touch screen with a hybrid powertrain display. This feature showed the vehicle operation regarding the interplay between gasoline engine, battery pack, and electric motors, and could also show a bar graph of fuel economy results.^[18]

In the United States, the NHW11 was the first Prius to be sold. The Prius was marketed between the smaller Echo and the larger Corolla. The published retail price of the car was US$19,995.^[19] The California Air Resources Board (CARB) classified the car as a Super Ultra Low Emission Vehicle (SULEV).^[20] Prius owners were eligible for up to a US$2,000 tax credit from their gross income.^[18] In contrast with the prior generation model, Toyota executives claimed that the company broke even financially on sales of the NHW11 Prius.^[18]

European sales began in September 2000.^[21] The official launch of the Prius in Australia occurred in 2001 after the Sydney Motor Show,^[22] although sales were slow until the NHW20 model arrived.

In 2006, Toyota recalled about 8,500 2001 and 2002 model year Prius vehicles due to an incorrectly manufactured crankshaft position sensor.^[23]

In 2009, after being investigated by the California Air Resources Board, Toyota extended a campaign nation-wide for owners of MY 2001-2003 Prius for starting problem caused by improper working throttle body that led to electronic control module malfunction.^[24]

2004–2009 (model NHW20)

NHW20 (Second Generation)

Production	2004–2009 (North America, Japan) 2004–present (China, Europe)
Model year(s)	2004–2009
Assembly	Tsutsumi, Japan (Toyota City) Kariya, Aichi, Japan (Fujimatsu) Chengdu, Sichuan, China (Chinese domestic market only)
Class	Mid-size car
Body style(s)	5-door hatchback
Engine(s)	Toyota Hybrid System II Gasoline: 1.5 L 1NZ-FXE DOHC I4 VVT-i 57 kW (76 hp) @ 5000 rpm 115 N·m (85 lb·ft) @ 4200 rpm Electric: 500 V 50 kW (67 hp) @ 1200 rpm 400 N·m (295 lb·ft) @ 0 rpm AT-PZEV Hybrid system net horsepower: 110 hp (82 kW)
Transmission(s)	1-speed planetary gear
Wheelbase	2,700 mm (106.3 in)
Length	4,450 mm (175.2 in)
Width	1,725 mm (67.9 in)
Height	1,490 mm (58.7 in)
Curb weight	1,317 kg (2,900 lb)

In 2004, the Prius was completely redesigned as a mid-size liftback, sized between the Corolla and the Camry, with redistributed mechanical and interior space significantly increasing rear-seat legroom and luggage room. The 2004 Prius is even more environmentally-friendly than the 2001 model (according to the EPA), and is 6 inches (150 mm) longer than the previous version.^[25] Its more aerodynamic Kammback body balances length and wind resistance resulting in a drag coefficient ( C_d) of 0.26.^[26] The development effort, led by chief engineer Shigeyuki Hori, led to 530 patents for the vehicle.^[27]

2006 Prius cut-away in a Toyota showroom in Paris

Toyota Prius plug-in hybrid prototype exhibited at the Automotive Engineering Exposition 2008, Yokohama City, Japan

An Australian Federal Police Prius

The Prius uses an all-electric A/C compressor for cooling, an industry first,^[28] and also adds an electric power steering system to further minimize engine belt-driven engine accessories. Combined with a smaller and lighter NiMH battery, the NHW20 is more powerful and more efficient than the NHW11.^[29] In the U.S., the battery pack of the 2004 Prius is warranted for 100,000 miles (160,000 km) or 8 years.^[30] The warranty for hybrid components in California and the seven Northeastern states that have adopted the stricter California emission control standards is 150,000 miles (240,000 km) or 10 years.

It is classified as a SULEV (Super Ultra Low Emissions Vehicle) and is certified by California Air Resources Board as an "Advanced Technology Partial Zero Emission Vehicle" (AT-PZEV).^[31]

Among the Prius's options are Toyota's implementation of a Smart Key System (the feature can be user-deactivated), DVD navigation on the MFD, Vehicle Stability Control and Bluetooth for hands-free calling. A new Intelligent Parking Assist system was available in Japan and Europe since its launch.^[32]

Production of the Prius for the Chinese market began in December 2005 with a target of 3,000 unit sales^[33] by Sichuan FAW Toyota Motor, a joint venture with First Automobile Works. It was reported that a total of 2,152 Prius were sold in 2006 and 414 in 2007. The relatively low sales was blamed on high price, about US$15,000 higher than the equivalent in Japan or the U.S., caused by high duties on imported parts.^[34] In early March 2008, Toyota cut the price of Prius by up to eight percent or US$3,000 to 259,800 CN元 (US$36,500). It was thought that the sales dropped as a result of both a lack of acceptance and increased competition. The Honda Civic Hybrid was imported to China from 2007.^[35]

Toyota's design and development efforts paid off during the 2005 European Car of the Year competition where the Prius won ahead of the Citroën C4 and the Ford Focus . The Prius is the only hybrid car so far to have won this competition, where the usual winners are mainstream hatchbacks and sedans/saloons from major European manufacturers.

Research plug-ins

From 2006 to 2009 Toyota tested 126 Prius models in the U.S., Japan and Europe that had the NiMH battery replaced with a lithium-ion battery pack.^[36]

In July 2007, Toyota received both Japanese and American governmental approval to begin testing plug-in hybrid models using a modified NiMH battery on public roads.^[37] The first plug-in Prius in America went to South Carolina.^[38] Researchers at the Advanced Power and Energy Program at the University of California, Irvine and the Institute of Transportation Studies at the University of California, Berkeley began testing two specially made Prius and analyzing driver behavior, study air quality and energy use.^[39][40]

Model year changes

2005 (2006 US model year) introduced some minor cosmetic changes, such as a higher-resolution liquid crystal display, as well as new optional features such as a backup camera, advanced air bags and an upgraded audio system with an auxiliary input. In 2006 (2007 US model year) the Prius added side-curtain air bags (standard on all models.) A Touring Edition was introduced, with an elongated and larger rear spoiler as well as larger, sharper-pointed 7-spoke 16" alloy wheels with plastic hubcap covers to protect them from scratches when parking against the curb. The Touring Edition also comes with a firmer European-style tuned suspension, standard high-intensity-discharge (HID) headlights and integrated (non-HID) fog lights.

In 2005, Toyota had to fix a software glitch that caused the Prius engine to enter "limp" mode with only-electric operation, following 68 stall complaints in the U.S.^[41][42][43] In June 2006, Toyota also recalled about 170,000 Prius models from 2004-2006 due to a faulty intermediate shaft and sliding yoke in the power steering system.

Crash testing results

NHTSA (United States) crash testing of the 2004 US model year Prius yielded a five-star driver and four-star passenger rating in the frontal-collision test (out of five stars). Side crash results were four out of five stars for both front and rear seats. The car scored four out of five stars in rollover testing.^[44]

IIHS crash tests score the Prius "Good" overall in frontal collisions and "Good" overall in side-impact collisions in models equipped with side airbags.^[45] A "Poor" score is given to models without side airbags.^[46] Side curtain and torso airbags became standard on 2007 American models.

In 2004, EuroNCAP tested the Prius. It earned the following ratings: Adult Occupant: Child Occupant: Pedestrian: .^[47]

2009– (model ZVW30)

ZVW30 (Third Generation)

Production	Mar 2009–present
Model year(s)	2010–present
Assembly	Tsutsumi, Japan (Toyota City)[48] Chengdu, Sichuan, China[49] (Chinese domestic market only)
Class	Mid-size car
Body style(s)	5-door hatchback
Engine(s)	Toyota Hybrid System Gasoline engine: 1.8 L 2ZR-FXE I4 Dual VVT-i (Atkinson cycle) Power: 98 hp @ 5,200 rpm Torque: 105 lb-ft @ 4,000 rpm[50]
Transmission(s)	1-speed planetary gear
Wheelbase	2,700 mm (106.3 in)
Length	4,460 mm (175.6 in)
Width	1,745 mm (68.7 in)
Height	1,480 mm (58.3 in)
Curb weight	1379 kg (3,042 lb)

Toyota debuted the new Prius (2010 US model year) at the 2009 North American International Auto Show,^[51] and sales began in Japan on May 18, 2009.^[52] Its new body design is more aerodynamic, with the coefficient of drag reduced to 0.25 C_d. An underbody rear fin helps stabilize the vehicle at higher speeds.

The estimated fuel-efficiency rating using the U.S. EPA combined cycle is: 50 mpg_-US (4.7 L/100 km; 60 mpg_-imp).^[53] The Prius was the most efficient car powered by liquid fuel available in the U.S. in 2009, based on the official rating.^[1] Only the first-generation Honda Insight (2000–2006) equipped with a manual transmission attained higher mileage. The official UK fuel efficiency data for the Prius T3 is: Urban 72.4 mpg_-imp (3.90 L/100 km; 60.3 mpg_-US), Extra Urban 76.4 mpg_-imp (3.70 L/100 km; 63.6 mpg_-US), Combined 72.4 mpg_-imp (3.90 L/100 km; 60.3 mpg_-US).^[54]

The 1.8-liter gasoline engine (previously 1.5 liters) generates 98 hp, and with the added power of the electric motor, total horsepower is 134 hp (previously 110 hp). The larger engine displacement allows for increased torque, reducing engine speeds (RPM), which increases fuel economy at highway speeds. With an electric water pump, the Prius engine is the first production engine that requires no accessory belts, which also further improves fuel economy.^[55] The electric motors and other components of the hybrid powertrain are also smaller and more efficient.^[56] Toyota estimates the new inverter, motor and transaxle are 20 percent lighter. Disc brakes replace the previous rear drum brakes.

Many motoring reviewers praised the 3rd generation for its improved handling in corners and more supple ride over the previous generation. http://www.edmunds.com/toyota/prius/2010/testdrive.html

Interior

For the Prius, Toyota used a new range of plant-derived ecological bioplastics made from the cellulose in wood or grass instead of petroleum. The two principal crops are kenaf (a member of the hibiscus family and related to cotton and okra) and ramie, commonly known as China grass and one of the strongest natural fibres, similar to flax in absorbency and density. Toyota says this is a particularly timely breakthrough for plant-based eco-plastics because 2009 is the United Nations’ International Year of Natural Fibres, which covers kenaf and ramie.^[57]

In Japan, it is reported that Toyota cut the price of Prius from 2.331 million yen to 2.05 million yen to compete with Honda Insight.^[58] Toyota filed over one thousand patents during the development of the latest Prius. Toyota's goal is to sell about 400,000 units annually around the globe ^[59] and 180,000 units in the U.S. by 2010.^[60] In May 2009 production was increased to 50,000 units per month or 600,000 annual units to help meet higher than projected demand.^[61] In 2009, Toyota Prius experienced two consecutive year over year sales decrease to 139,682 units in the U.S., from 181,221 units in 2007.^[62] In addition, Toyota Prius was launched in Malaysia on August 4, 2009.^[63]

In early 2010, Toyota considered adding a monthly production of 6,000 at the Motomachi factory, in central Japan, the plant that built the first-generation Prius in 1997. However, as customers' wait time in Japan shortened from eight months at launch to three months, and sales in the United States dropped 40 percent in February 2010 from October 2009 following concerns about Toyota vehicles' safety, Toyota had to reduce the monthly production by 10 percent to 45,000 units a month in March 2010.^[64]

In the US the Prius will have a starting base price of US$22,400 excluding destination charges, and includes 15-inch alloy wheels, Vehicle Stability Control and interior amenities including cruise control, 6-speaker audio, Toyota's keyless entry/ignition Smart Key System and a unique Touch Tracer Display designed to help the driver's eyes stay on the road when using the steering-wheel-mounted climate and audio controls.

2009 Toyota Prius (Australia)

Sales of the Prius also started in the Philippines on June 22, 2009, for a SRP of Php 2.2 million (approximately US$41,800) about half for import duties and other taxes, making it the first hybrid vehicle available in the Philippines.^[65] The launching for the Latin American market took place in Costa Rica on July 3, 2009. The Prius will be sold in Costa Rica for US$41,000 including tariffs and all taxes.^[66]

The US Prius offers three optional packages:

• A Navigation Package that includes a voice-activated touch-screen DVD-based navigation system and an 8-speaker JBL audio system with XM satellite radio, MP3/WMA playback capability, Bluetooth and backup camera. The Prius in Japan is equipped with G-Book as of May 18, 2009.^[67]
• A Solar Roof Package includes the Navigation Package and adds a power tilt/slide moonroof along with a solar powered ventilation system that uses an electric fan to help keep the vehicle cooler when parked under the sun by venting the interior's heated air with the outdoors. The solar roof was originally intended to assist in charging the vehicle's battery, but the system was configured to only power ventilation when it was found that the battery-charging configuration created electromagnetic interference that affected the radio.^[68] A new remote air-conditioning feature allows the driver to activate the air conditioner prior to entering the vehicle.
• An Advanced Technology Package includes the Navigation Package while adding a Pre-Collision System, Dynamic Radar Cruise Control, Lane Keep Assist and Intelligent Parking Assist.

Other options include Safety Connect, while LED headlamps come standard on the Prius V trim.^[69]

In May 2010, Toyota Prius was launched in India with a price from Rs.26.55 lakhs to Rs.27.86 lakhs (ex showroom Delhi).^[70]

Plug-in version

Prius Plug-in at the Frankfurt Motor Show

The Prius Plug-In Concept was shown at the October 2009 Tokyo Motor Show, the 2009 Frankfurt Motor Show, and the 2009 LA Auto Show. According to Toyota a total of 500 Prius plug-in hybrids (PHEV) will be sold to select customers, 350 will be delivered to customers in Europe and Japan in late December 2009, along with 150 models to be released in the U.S. in early 2010.^[71] These models will be sent to limited geographical areas and will contain special data tracking devices designed to allow Toyota to monitor the car's usage for further development of the plug-in hybrid system.^[72] Total all-electric range is 14.5 mi (23 km) with speeds up to 62 mph (100 km/h). The lithium-ion battery was co-developed with Panasonic.

Toyota announced a target of retail sales for the PHEV in late 2011. Toyota indicates that it plans to sell tens of thousands of plug-ins to the public.^[73][74]

Crash testing results

The IIHS rated the 2010 Prius as Good in every crash category except for "structure/safety cage," which was rated Acceptable. ^[75] In EuroNCAP testing the Prius is given an overall rating of , and rated 88% for adult occupant protection, 82% for child occupant, 68% for pedestrian, and 86% for safety assist.^[76]

Brake fix and radar cruise

On February 9, 2010, Toyota announced a voluntary global recall of third generation 2010 Prius models manufactured from the current model's introduction through late January.^[77][78] Affected models, including 133,000 Prius vehicles in the U.S. and 52,000 in Europe, are to receive an anti-lock brake software update to fix brake response over rough roads,^[77] following reports of delayed braking response on certain surface conditions.^[79][80] Apple co-founder and Prius collector Steve Wozniak was also quoted by media outlets regarding a possible cruise control issue on one of his several Priuses, where the steps for "upping the speed" using the Dynamic Radar Cruise Control system allegedly caused unintended acceleration.^[81] Wozniak later maintained that he was misquoted, but did have an individual vehicle and customer service issue,^[81] while auto journalists and other Prius drivers suggested user error.^[82][83] On March 8, 2010, a publicized incident of alleged Prius acceleration in San Diego was later suspected to be a hoax or not repeatable.^[84][85][86]

Comparison of models

Background

History

In 1994, Toyota executive Takeshi Uchiyamada was given the task of creating a new car that would be both fuel efficient and environmentally friendly.^[87] After reviewing over 100 hybrid designs, the engineering team settled on a hybrid engine design based on a 1974 TRW patent, but many technical and engineering problems had to be solved within the three years that the team was given to bring the car to the Japanese market, a goal they barely achieved as the first Prius went on sale in December 1997. A main problem was the longevity of the battery, which needed to last between 7 and 10 years. The solution the engineers came up with was to keep the battery pack between 60% and 40% charged, proving to be the "sweet spot" for extending the battery life to roughly that of the other car components.^[88]

The car was a modest success in Japan and after gathering several years of test data from the Japanese early adopters, the company felt it was safe to put it on sale in the U.S. and European markets in 2001. Sales were limited and customer waiting lists of up to 6 months were common during the first few years. In 2004, a complete redesign, increased production, and soaring fuel prices led to significant increases in sales.

Name

"Prius" is not a verb but a Latin comparative adjective or adverb, the neuter nominative singular form of the adjective whose corresponding masculine and feminine nominative singular forms are prior^[89] (see also Latin declension - Irregular adverbs and their comparative and superlative forms) with meanings "ahead, in front, leading; previous, earlier, preceding, prior; former; basic."^[90]

A Toyota spokesperson stated that "Toyota chose this name because the Prius vehicle is the predecessor of cars to come."^[91]

Some enthusiasts enjoy using "Prii" as the plural, which would be correct if "prius" were a regular second declension Latin noun. The actual Latin plural of the adjective is "priora" (Reference ^[91] is slightly in error here). All of these forms are nominative case and there are several other forms for the other cases. As for the plural of "Prius" in English, Toyota has said that it is simply "Prius" and also that owners are welcome to use whatever they like.^[92]

Sales

2006 Toyota Prius used by a car share agency.

The Prius is sold in more than 50 countries and regions, and has its largest markets in the United States, Japan, and Europe. In May 2008, Toyota announced that its worldwide cumulative sales of the Prius had passed the 1 million mark;^[3] worldwide cumulative sales reached 1.8 million Prius in June 2010;^[5] and Toyota is expecting to reach the two million milestone by the boreal autumn of 2010.^[93]

As of December 2009 the U.S. accounted for almost half of the Prius global sales, with 814,173 Prius units registered since 2000.^[6] Cumulative Prius sales in Europe reach 100,000 in 2008 and 200,000 units by mid 2010, after 10 years on that market. The U.K. is one of the leading European markets for Prius, accounting more than 20 percent of all Prius sold in Europe.^[93]

Toyota Prius became Japan's best selling vehicle in 2009 for the first time since its debut in 1997 as its sales almost tripled to 208,876 in 2009.^[94] In that year it overtook the Honda Fit, which was Japan's best-selling car in 2008 excluding Kei cars. It led to analyst questioned that the increase of sales of Prius might come at the cost of vehicles that could bring in higher margin. Competition from lower priced hybrid like Honda's Insight also made Toyota difficult to capitalize on Prius's success.^[95]

Design and technology

The Toyota Prius Hybrid Synergy Drive is a series-parallel full hybrid, sometimes referred to as a combined hybrid.

The Prius is a power-split or series-parallel (full) hybrid, sometimes referred to as a combined hybrid, a vehicle that can be propelled by gasoline and/or electric power. Components of the system include:

1. Regenerative braking, using motor-generators, which converts kinetic energy of motion into electrical energy that is stored in the traction battery, giving better braking performance and reducing wear on the brake pads;
2. A 1NZ-FXE internal combustion engine (ICE) using Atkinson cycle, which is 12-14%^[99] more efficient than the more powerful Otto cycle. The gasoline engine normally shuts off during traffic stops and the accessories (including the air conditioning) are powered by the battery pack. The engine is used both to propel the vehicle and to recharge the batteries. Because of the availability of extra power from the electric motors for rapid acceleration (at lower speeds), the engine is sized smaller than usual for increased fuel efficiency and lowered emissions with acceptable acceleration (at lower speeds). The penalty of the Atkinson cycle is low specific power, so the battery and generator are needed to give extra power when accelerating, whilst allowing the vehicle to cruise on the low powered engine;^[100]
3. Two electric motor/generators: MG1 and MG2. MG1, reversible and up to 10,000 rpm, starts the engine and provides counter torque for the Continuously Variable Transmission (CVT). MG2 provides 50 kW (67 hp) between 1,200 to 1,540 rpm and 400 N·m (295 lb·ft) torque between 0 to 1,200 rpm, contributing to performance and economy. These motor-generators are used as generators when in regenerative braking mode, and as motors are capable of powering the vehicle at low speed (<~30 mph (48 km/h), 41 mph (66 km/h) in NHW20) travel. Each electric motor requires 1 kilogram (2.2 pounds) of neodymium;^[101]
4. A Hybrid Synergy Drive (HSD) unit that combines a planetary gearset that behaves like a Continuously Variable Transmission (CVT) called the Power Split Device^[102] to increase efficiency. The computer controlled HSD transaxle adjusts and blends the amount of power from the gasoline engine and electric motor-generator(s) as needed by the front drive wheels and rechargeable batteries.
5. A sealed 38-module nickel metal hydride (NiMH) battery pack providing 273.6 volts, 6.5 A·h capacity and weighing 53.3 kg (118 lb)^[103] is supplied by Japan's Panasonic. They are normally charged to 40–60% of maximum capacity to prolong battery life as well as provide a reserve for regenerative braking. Each battery uses 10 to 15 kilograms (22 to 33 pounds) of lanthanum;^[101]
6. Wind resistance is reduced by a drag coefficient of 0.25 (0.29 for 2000 model) with a Kammback design to reduce air resistance. Lower rolling-resistance tires are used to reduce road friction;
7. A vacuum flask for storing hot coolant when the vehicle is powered off for reuse so as to reduce warm-up time (US market);
8. An EV mode that allows drivers to operate on electric power only under low-power conditions for a limited duration of time.
9. Vehicle weight is reduced by the use of a flexible resin gasoline tank and by the use of aluminum instead of steel for the engine bay hood and hatchback;
10. Starting with the 2010 model (3rd generation), the new 1.8 liter 2ZR-FXE gasoline engine will feature advanced technologies such as the Atkinson cycle, a cooled EGR (Exhaust Gas Recirculation) system, intake-side VVT-i, and an electric water pump, permitting an engine design with no serpentine belts, improving efficiency.^[104]

THS inverter unit (from NHW11)

The computer program used in the Prius shuts off the engine when the car is stopped, is reversing, or is descending hills, thereby dramatically decreasing fuel consumption in city driving. The HSD's on-board computer program determines when and how to use the engine, motor, or both to power the car and recharge the battery so as to maximize efficiency. Typically, a gasoline engine runs inefficiently at half-throttle, creating a choking condition called pumping loss, a major reason for the inefficiency of gasoline engines compared to diesels. The Prius minimizes pumping loss by using a high torque range as much as possible with the throttle fully open. Drive-by-wire throttle control technology and Toyota's Hybrid Synergy Drive (a torque combiner, electric drive, and computer control) are essential to this engine control.

Energy monitor on the 2005 Prius multi-function display (MFD), showing energy flow to/from the engine, battery, and from the regenerative braking, as well as battery charge level.

Hybrid Synergy Drive

Typical gasoline- or diesel-engined vehicles consume fuel when the vehicle is stopped, as is common in city driving. The Prius typically shuts down the gasoline engine and runs solely off the battery pack at low speeds and when stopped. A non-hybrid car also gets worse fuel consumption in city driving because its engine is continually used to accelerate the car to driving speed and then this energy is lost to friction brakes during stop-and-go driving. The Prius recaptures some of this energy by using regenerative braking to charge its battery pack while slowing down with its motor-generators in generator mode. For acceptable acceleration, the internal combustion engine on a "standard" car typically is much larger than needed for constant-speed travel, and is a relatively high power-to-weight ratio Otto cycle engine. By using both an Atkinson cycle gasoline engine, which whilst more efficient has a much poorer power to weight ratio, and an electric motor for acceleration, the Prius engine can nevertheless be a smaller size and still provide acceptable acceleration.^[100] This means such a hybrid can have high fuel efficiency (but slower top speed than comparable non-hybrid vehicles) when using the Atkinson cycle engine for cruising or city driving, though factors including driving style, air conditioning use, and short trips may offset some of this advantage. The frequent starting and stopping of the Prius engine does not cause noticeable additional wear or emission problems because the electric drive motors have enough power to quickly spin the engine to optimal speed (around 1,000 rpm) before fuel is admitted.

Energy screen on the 2003 Prius

For any car, aerodynamic losses, which vary roughly as the velocity squared due to air drag are much greater on the highway than in low speed city driving. The Prius hybrid has less of an advantage in higher speed open road driving, typical of intercity driving. Nevertheless, the Prius still obtains improved fuel consumption under these circumstances since it can use a smaller and more efficient engine than would otherwise be required. The electric motor(s), powered by the battery pack, can provide the extra peak power needed for acceleration, passing and limited hill climbing. With low weight and the lowest drag coefficient of a production car in the U.S. market, the Prius is a very efficient^[1][105] highway traveler, getting 48 mpg_-US (4.9 L/100 km; 58 mpg_-imp) on the highway according to the U.S. EPA.

The environmental impact of the car's batteries has been questioned, though Toyota offers a US$200 "bounty" for recycled batteries to try and prevent any toxins from entering the environment.^[106] An independent commodities consultant called the Prius "the biggest user of rare earths of any object in the world."^[107] To encourage battery recycling, dealers are paid a US$200 fee for return of the car's batteries.^[108] Toyota has laboratory reports that some Prius battery packs have lasted the equivalent of 180,000 miles (290,000 km).^[103] As the cars start to age, early reports have shown that in at least some cases the batteries can last in excess of 250,000 miles (400,000 km).^[109] Individual battery longevity will vary depending upon the treatment and use history of the battery pack. A degraded battery pack will reduce performance and fuel economy, but not leave the car inoperable.

EV mode

When the vehicle is turned-on with the "start" button, it is ready to drive immediately with the electric motor, while electric pumps warm the engine with previously saved hot engine coolant, before the internal combustion engine is started. The delay between starting the car and starting the internal combustion engine is approximately seven seconds. A button labeled "EV" maintains Electric Vehicle mode after start up and under most low-load driving conditions. This permits driving with low noise and no fuel consumption, and is advertised as a "quiet" option for short journeys, for example in residential areas at night, in the Asia manual. The car automatically reverts to normal mode if the battery becomes exhausted. Prior to the 2010 model, the North American model did not have the "EV" button, although the "EV" mode is still supported internally by the Prius Hybrid Vehicle management computer.

Fuel consumption

Monitor on a 2005 Toyota Prius MFD, displaying accumulative fuel economy for 59 miles (95 km) since last gasoline fill-up.

Fuel consumption, or fuel-efficiency in cars is generally measured as distance travelled per unit volume of fuel, as in miles per gallon (mpg), or as the volume of fuel required to cover a given distance, as in liters per 100 kilometres (L/100 km). Diesel fuel does have about an 11% higher energy density than gasoline, so that needs to be taken into account in pure energy-efficiency calculations and comparisons. Fuel-price-efficiency calculations will vary between various parts of the world, with diesel fuel pump prices being higher than gasoline prices in some countries, whilst in others it is less expensive than gasoline.^[110]

Official government data

United States

In the United States, the Environmental Protection Agency (EPA) test results must be posted on new vehicle windows, and are the only fuel consumption figures that can be advertised. EPA testing procedures for all vehicles were revised in 2007 in an attempt to better match what the average driver would achieve.^[111] The following data is taken from these figures:^[112]

2010 Prius:

• 51 mpg_-US (4.6 L/100 km; 61 mpg_-imp) city driving
• 48 mpg_-US (4.9 L/100 km; 58 mpg_-imp) highway driving
• 50 mpg_-US (4.7 L/100 km; 60 mpg_-imp) combined

2005 Prius:

• 48 mpg_-US (4.9 L/100 km; 58 mpg_-imp) city driving
• 45 mpg_-US (5.2 L/100 km; 54 mpg_-imp) highway driving
• 46 mpg_-US (5.1 L/100 km; 55 mpg_-imp) combined

2001 Prius:

• 42 mpg_-US (5.6 L/100 km; 50 mpg_-imp) city driving
• 41 mpg_-US (5.7 L/100 km; 49 mpg_-imp) highway driving
• 41 mpg_-US (5.7 L/100 km; 49 mpg_-imp) combined

The Prius is the most efficient car powered by liquid fuel available in the U.S. in 2009, based on the official EPA rating.^[1] Only the first-generation Honda Insight equipped with a manual transmission attained higher mileage, however, that vehicle is not made any more, making the Prius the most efficient car on sale in 2010.

United Kingdom

The official fuel consumption data, provided by the Department for Transport, rates the Prius as: 56.5 mpg_-imp (5.00 L/100 km; 47.0 mpg_-US) urban, 67.3 mpg_-imp (4.20 L/100 km; 56.0 mpg_-US) extra urban and 65.7 mpg_-imp (4.30 L/100 km; 54.7 mpg_-US) combined.^[113] Eleven diesel-powered vehicles with manual transmissions, most of them smaller cars have better fuel-efficiency (by fuel volume) than the second generation Prius for combined use.^[114][115]

The third generation Prius is rated at 72.4 mpg_-imp (3.90 L/100 km; 60.3 mpg_-US) combined. Ten diesel powered cars match or exceed that figure.^[114]

Independent comparison tests

Several organizations have tested the fuel economy of the Prius and compared it directly with other cars.

Consumer tests have shown that gasoline-electric hybrid cars in general are a little more fuel-efficient (by fuel volume) than top of the range manual transmission diesels.^[116] However, diesel fuel has a significantly higher energy density than the gasoline used by the Prius, and in some countries diesel is less expensive than gasoline, so overall diesel with manual transmission may be competitive with hybrid technology in some cases.^[110]

• January 2010: Road and Track compared the redesigned Prius with the Volkswagen Golf TDI and Ford Fiesta on seven separate routes, and twice comparing the vehicles at a 70 mph (110 km/h) cruising speed either with or without the air conditioning. The Prius returned the highest mileage in all the tests with an overall average of 54.5 mpg_-US (4.3 L/100 km; 65.5 mpg_-imp) over 336 miles (541 km), the Golf returned 42.7 mpg_-US (5.5 L/100 km; 51.3 mpg_-imp) and the Fiesta 34.0 mpg_-US (6.9 L/100 km; 40.8 mpg_-imp).^[117]

• September 2009: In a MotorWeek and Cars.com comparison of the Honda Insight, Audi A3 TDI, Volkswagen Jetta TDI, Smart ForTwo and Ford Fusion Hybrid, the Prius returned the highest mileage with 49.2 mpg_-US. The Insight ranked second most fuel efficient managed 40.5 mpg_-US.^[118]

• January 2009: Edmunds.com compared the 2009 Prius to the all-new 2010 Insight. The Prius returned 54.4 mpg_-US compared to the Insight's 51.5 mpg_-US.^[119]

• September 2008: A Popular Mechanics comparison shows that the 2009 Jetta TDI diesel has slightly better highway fuel economy than the 2008 Prius with 45.4 mpg_-US compared to 44.8 mpg_-US. The Prius did better than the Jetta in city fuel economy, however: 44.7 mpg_-US compared to 32 mpg_-US.^[120]

• August 2008: Edmunds.com test of Prius and Honda Fit, resulted in the Prius averaging 42 mpg_-US (5.6 L/100 km; 50 mpg_-imp), while the compact-sized non-hybrid Fit averaged 28 mpg_-US (8.4 L/100 km; 34 mpg_-imp).^[121]

• June 2009: The Prius is the most fuel efficient car that Consumer Reports has tested^[122] since the discontinuation of the 3-door Honda Insight. Consumer Reports recorded 44 mpg_-US (5.3 L/100 km; 53 mpg_-imp) over its tests simulating real-world driving conditions for the Prius.^[123]

• May 2008: The Prius was the overall winner of the Edmunds.com "Gas-Sipper Smackdown" fuel economy test, winning three of the five tests including lowest overall fuel costs. The 2005 Jetta TDI won the remaining two tests, but factoring in the higher cost of diesel the Jetta ranked third in fuel costs behind both the Prius and Smart Fortwo. The other car tested was the North American Ford Focus.^[124]

• March 2008: The UK's Sunday Times did a comparison of the Prius and the BMW 520d SE with a 177 bhp (132.0 kW) diesel engine, 6-speed manual transmission and regenerative braking, which averaged 50.3 mpg_-imp (5.62 L/100 km; 41.9 mpg_-US) whilst the Prius averaged 48.1 mpg_-imp (5.87 L/100 km; 40.1 mpg_-US) over exactly the same route. The comparison was performed on a journey of 545 miles (877 km) from London to Geneva, including 100 miles (160 km) of urban driving, about 200 miles (320 km) of driving on rural roads, and about 200 miles (320 km) of motorway driving at speeds of up to 78 miles per hour (126 km/h) on one French autoroute.^[125]

• August 2007: UK's Auto Express magazine performed independent fuel efficiency tests, on public roads, on a number of hatchbacks, and in August 2007 published their list of the ten most efficient. The Prius achieved 10th place in the list, returning 41.5 mpg_-imp (6.81 L/100 km; 34.6 mpg_-US). A Citroën C4 Coupé 1.6 HDi got 1st place with 49.6 mpg_-imp (5.70 L/100 km; 41.3 mpg_-US).^[126]

• Motor Trend conducted a test comparing the Prius with a Civic Hybrid. The Prius had the better fuel economy with 43.8 mpg_-US (5.37 L/100 km; 52.6 mpg_-imp) compared to 39.9 mpg_-US (5.90 L/100 km; 47.9 mpg_-imp) for the Civic.^[127]

• December 2005: Edmunds.com test of the Prius and Civic Hybrid resulted in the Prius outperforming its competitor by an additional 4.5 mpg_-US (52 L/100 km; 5.4 mpg_-imp) at 48.3 mpg_-US (4.87 L/100 km; 58.0 mpg_-imp).^[128]

• February 2005: In a Popular Mechanics magazine diesel versus hybrid comparison, the Prius outperformed the Jetta TDI diesel in both city and highway fuel economy.^[129][130]

• September 2004: Car and Driver tested the Prius, the Civic Hybrid, Echo, and Jetta TDI over three separate routes. The Prius yielded the best mileage on the highway and town routes, while tying the Echo for top spot on the suburban route.^[131]

• July 2008: The British automotive show Top Gear ran a controversial test, in which a Prius was tested against a BMW M3, a tuned sport sedan. The Prius was instructed to drive as fast as possible for 18 miles, while the M3 had to keep up. At this speed, the M3 got 16.1 mpg, while the Prius got just 14.3 mpg. However, host Jeremy Clarkson explained the test was meant to illustrate that the driving style has more to do with fuel economy than the car itself.^[132]

Air pollution

In the United States the EPA measures a vehicle's air-borne pollution based on hydrocarbons, nitrogen oxides, carbon monoxide, particulate matter and formaldehyde before assigning them a score.^[133] In most states the NHW20 Prius is rated Tier II Bin 3.^[134] CARB also does its own emission scoring, the NHW20 Prius meets AT-PZEV certification in California and states that adopted CARB emission rules.^[135]

CO₂ emission

According to the UK Department for Transport, the third-generation Prius launched in the UK in August 2009 emits 89 g/km, overtaking other cars except the two seat Smart fortwo with its 0.8 liter turbocharged 45 hp diesel, which emits 88 g/km.^[136]

The previous Prius tied with the MINI Cooper D as the fourth least CO₂-emitting vehicles at 104 g/km, behind the Ford Fiesta Econetic at 98 g/km and the tied Volkswagen Polo 1.4 TDI/SEAT Ibiza 1.4 TDI at 99 g/km - it is the least CO₂-emitting gasoline powered car, since the Ford and the Polo/Ibiza (both of which are city cars) run on diesel.

Criticisms

CO₂ advertising claims

In the UK, the Advertising Standards Authority, an independent body charged with policing the rules of the advertising industry, ruled that a television advert for the Toyota Prius should not be broadcast again in the same form, having breached rules concerning misleading advertising. The advert claimed the Prius "emits up to one tonne less CO₂ per year," while on-screen text included: "1 tonne of CO₂ less than an equivalent family vehicle with a diesel engine. Average calculated on 20,000 km a year." Points of contention were the vehicles chosen for comparison, whether "up to one tonne less" adequately communicated that reductions could be lower, and whether the distance used was appropriate: 20,000 km per year is around a U.S. car's average annual driving distance, while a UK car's is 13,440 km.^[137]

An earlier complaint to the New Zealand Advertising Standards Authority, decision 03/360 2003 was also upheld. It was ruled that Toyota was in breach of the New Zealand advertising standards code of ethics, by claiming "up to 89% fewer smog forming emissions”. The figure was based on comparison with Euro 3 standards, which most new cars also met comfortably at the time.

Lifetime energy usage

The British Government and British media have requested Toyota release detailed figures for the energy use and CO₂ emissions resulting from the building and disposal of the Prius. The UK Government Car Service runs 130 Priuses. Toyota has not supplied the detailed data they requested to support claims that the lifetime energy usage of the Prius (including the increased environmental cost of manufacture and disposal of the nickel-metal hydride battery) are outweighed by lower lifetime fuel consumption.^[138] Toyota states that lifetime CO₂ saving is 43 percent.

CNW Marketing Research initially published a study^[139] in which they estimated that the total lifetime energy cost of a Prius was greater than that of a Hummer. The study is widely cited, and its contents have also been widely challenged: see for example "Hummer versus Prius: 'Dust to Dust' Report Misleads the Media and Public with Bad Science."^[140] A recent update by CNW has changed the total lifetime cost value, now placing the Prius as costing less than the Hummer.

Repair costs

According to a study by Audatex, Prius repairs are slightly more expensive than those for comparable non-hybrid cars, with a greater cost difference in the past because of the lack of availability of recycled parts.^[141]

Political symbolism

The large number of Prius-owning progressive celebrities in 2002 prompted the Washington Post to dub hybrids "Hollywood's latest politically correct status symbol."^[142] While conservative "Prius Patriots" were also cited in 2005,^[143] the vehicle carries an image as being a car for politically liberal environmentalists. A 2007 San Francisco Chronicle article said "Prius Progressives" were becoming an archetype, quoting conservative U.S. pundit Rush Limbaugh opining that "these liberals think they're ahead of the game on these things, and they're just suckers."^[144]

Some conservatives promote use of the Toyota Prius and other hybrid cars. For example, Jim Road from What Would Jesus Drive? encouraged people to drive hybrid cars because of the damage that large SUVs and/or faster cars can do to others.^[145]

Former Central Intelligence Agency chief R. James Woolsey, Jr. drives a Prius because of its low fuel consumption. Woolsey noted the volatility of the Middle East, coupled with anti-US sentiment in much of the region. Noting that the high percentage of oil drilled in the Middle East gives vast profits to Middle Eastern regimes, Woolsey believes that it is a patriotic obligation to drive more efficient vehicles. In a Motor Trend magazine article, Woolsey claimed that those oil profits find their way to terrorist groups like al-Qaeda, meaning that Americans who buy inefficient vehicles would, in effect, be indirectly funding terrorism. "We're paying for both sides in this war, and that's not a good long-term strategy," said Woolsey. "I have a bumper sticker on the back of my Prius that reads, 'Bin Laden hates this car.'"^[146]

Fashion over function

In 2004, industry analyst Art Spinella of CNW Marketing Research (CNWMR), whose skepticism towards hybrids is well known (see Lifetime energy usage), said "the Prius was a fashion statement," attributing its success over the Honda Civic Hybrid, which has a nearly identical appearance to its non-hybrid versions, to its distinctive styling, which lets "other people know the driver is driving a hybrid vehicle."

In July 2007 The New York Times^[147] published an article using data from CNW Marketing Research finding that 57% of Prius buyers said their main reason for buying was that "it makes a statement about me," while just 36% cited fuel economy as a prime motivator. Shortly afterwards Washington Post columnist Robert Samuelson coined the term "Prius politics" to describe a situation where the driver's desire to "show off" is a stronger motivator than the desire to curb greenhouse gas emissions.^[148]

Quietness

The Prius may pose a risk to pedestrians when operating in electric mode due to their lack of noise.

The Wall Street Journal reported in February 2007 on concerns that quiet cars like the Prius may pose a safety risk to those who rely on engine noise to sense the presence or location of moving vehicles.^[149] Blind pedestrians are a primary concern, and the National Federation of the Blind advocates audio emitters on hybrid vehicles,^[150] but increased risks may also affect sighted pedestrians or bicyclists who are accustomed to aural cues from vehicles. However there is also a lack of aural cues from vehicles that have a conventional internal combustion engine, where engine noise has been reduced by noise absorbing materials in the engine bay and noise canceling muffler systems. In July 2007, a spokesman for Toyota said the company is aware of the issue and is studying options.^[151] Both State^[152] and Federal legislation^[153] have been proposed and the National Highway Traffic Safety Administration held a public hearing.^[154] Different groups and companies are looking at solutions.^[155][156]

On August 2010 Toyota began sales of an onboard device designed to automatically emit a synthesized sound of an electric motor when the Prius is operating as an electric vehicle at speeds up to approximately 25 kilometres per hour (16 mph). The device will be available in Japan for retrofitting on the third-generation Prius at a price of ¥12,600 (~US$150) including the consumption tax. The alert sound rises and falls in pitch according to the vehicle's speed, thus helping indicate the vehicle's proximity and movement to nearby pedestrians. The device meets the Ministry of Land, Infrastructure, Transport and Tourism issued in January 2010 for hybrid and other near-silent vehicles.^[157]

Government and corporate incentives

Government incentives

A number of governments have incentives that are intended to encourage hybrid car sales.

Belgium

The Belgian national government offers reductions in the purchase price of up to 15% for buying cars that have lower CO₂ exhaust.^[158]

Canada

The Canadian federal government offered a rebate to those who bought or leased hybrid cars, however the rebate program expired on December 31, 2008.^[159] Some provincial governments also offer incentives such as in British Columbia,^[160] Manitoba,^[161] Quebec,^[162] Ontario until 30 June 2010,^[163] and Prince Edward Island.^[164]

Germany

In Germany there is no Government Incentive for hybrid vehicles, but since July 1, 2009, car tax ("Kraftfahrzeugsteuer") has been modified, taking into account engine displacement, type of engine (diesel/gasoline and Euro emissions standard category) and CO₂ emissions (before it was based on engine displacement, type of engine only and emissions standard category only).
Any car emitting less than 120g/km CO₂ pays only tax based on engine displacement. In particular €2 per every rounded 100 cm³ for gasoline engines (diesel engines pay €9.50, with concessions depending on the emissions category). An additional €2 is taxed per every additional gram emitted above the 120g/km limit. Due to this regulation all Prius 2010 registered after July 1, 2009 are taxed €36/year.
In comparison, all second generation Prius, registered for the first time before July 1, 2009 and after January 1, 2005 are currently paying €101/year.
The CO₂ emissions limit will be reduced in the coming years: in 2012 will be lowered to 110g/km and in 2014 to 95g/km. It is not clear whether this regulation will be retro-active, effectively raising the tax imposed on owners of cars emitting above the newly introduced limits. The tax imposed on all new Prius 2010 registered for the first time after July 1, 2009 will remain nevertheless €36/year (since the maximum CO₂ emissions rating is 92g/km), unless the taxation based on engine displacement is changed in the future.
More information on German car taxation can be found (in German only).

Netherlands

In the Netherlands, the government has lowered the tax for company-cars with CO₂ emissions below a certain level (such as the Prius) to 14%. The tax on all other class company-cars has been raised from 22 to 25%. As a result, in the month January alone, more than 1800 cars have been sold. The importer has already indicated that he can no longer meet the demand for the year 2008. Privately owned cars with low CO₂ emissions benefit from lower road taxes.

Sweden

In order to stimulate sales of less environmentally destructive vehicles, the Swedish government awards private purchasers of the Prius (and other qualifying cars) SEK 10,000 (roughly US$1,700, €1,100) after six months of ownership. This subsidy program has been very successful.

United Kingdom

In the U.K. there are both fiscal and parking-related incentives. The fiscal incentives are general; road tax is just GB£15 a year. Businesses can now (from 1 April 2008) claim a 100% first year tax write-off for the Prius because the car has CO₂ emissions of less than 110 grams per kilometre. The tax charge for a Prius that is provided as a company car is just 10% of its list price, rather than the heftier rates that can be up to 35% of a car's list price. Parking incentives exist in Richmond upon Thames (south west London),^[165] Westminster (Central London) for resident parking permits,^[166] Winchester (now discontinued),^{[167][168][169]} Manchester, and Brighton has similar plans.^[170] Drivers can pay GB£10 to register for an annual exemption from the GB£8 daily London congestion charge^{[170][171][172]} Some of the incentives in the United Kingdom have been criticized in the press given that non-hybrid cars, some of which may have better fuel economy and be more environmentally friendly to produce in some circumstances, are not afforded the same incentives.^[173][174]

Prius with California's clean air bumper stickers that allows free access to HOV lanes.

New York City Department of Transportation fleet of Prius.

United States

The U.S. federal government offers a tax credit to purchasers until a certain number of cars has been sold by a manufacturer. This has ranged from US$787 to US$3,150, which expired in 2007 for hybrids sold by Toyota.^[175] Some state governments, including Colorado,^[176]Connecticut,^[177] Illinois^[178] offer tax incentives.

Some hybrid automobiles are exempt from high-occupancy vehicle lane restrictions in some U.S. states, with California leading with 85,000 eligible hybrids, though the benefit for these cars expires on January 1, 2011.^[179] Los Angeles and San Jose, California had exempted hybrid cars from paying for street parking.^[180][181] New York State offers a special "green" version of their E-ZPass toll payment tag for hybrid owners who use the NYS Thruway system, which gives the owners a 10% discount on tolls.^[182] Also, the Port Authority of New York and New Jersey offers their "green E-ZPass" to hybrid owners, who pay US$4 instead of US$8 to use all the bridges and tunnels between New York and New Jersey, except in rush hours.^[183]

Corporate incentives

Several U.S. companies offer employees incentives. Bank of America will reimburse US$3,000 on the purchase of new hybrid vehicles to full- and part-time associates working more than 20 hours per week.^[184] Google,^[185] software company Hyperion Solutions,^[186] and organic food and drink producer Clif Bar & Co^{[184][broken footnote]} offer employees a US$5,000 credit toward their purchase of certain hybrid vehicles including the Prius. Integrated Archive Systems, a Palo Alto IT company, offers a US$10,000 subsidy toward the purchase of hybrid vehicles to full-time employees employed more than one year.^{[184][broken footnote]}

Clothing companies Timberland and Patagonia, law firm DLA Piper, non-profit American Jewish Committee, software publisher Topics Entertainment, Logistics Giant Exel Contract Logistics, and research firm ABR, Inc. are among companies offering eligible employees significant discounts on certain hybrid vehicles including the Prius.^{[184][broken footnote]}

Travelers Companies, a large insurance company, offers hybrid owners a 10% discount on auto insurance in most states.^[187] The Farmers Insurance Group offers a similar discount of up to 10% in most states.^{[184][broken footnote]}

Aftermarket products

Plug-in conversion

Toyota Prius plug-in hybrid converted by CalCars.

Plug-in hybrids use a larger electric vehicle battery pack, which is recharged from external sources to further reduce fuel consumption. The NiMH batteries^[188] in a production PHEV will be built to handle deeper discharge cycles without loss of lifespan such as the NiMH battery pack in the Toyota RAV4 EV. Operation of the vehicle will be very similar to a normal hybrid, except that the electric operation will be more prevalent. In the case of a Prius PHEV, on the highway, the gasoline engine will operate as before, leaving the car with the same ability to accelerate and use freeways. Current converted Priuses also operate in a high speed blended mode that can reduce but not eliminate fuel consumption on the freeway. When driving in slower conditions or with light loads, the car uses the batteries first in a charge-depleting mode, allowing moderate commutes (particularly under 41 mph/65 km/h) entirely on electricity. Once the batteries have been sufficiently discharged the car will automatically revert back to the charge-sustaining mode of the current stock Prius.

A Raleigh, North Carolina firm, Advanced Vehicle Research Center, converts the Prius by adding a second battery, improving its fuel efficiency by increasing the distance it runs on electricity alone.^[189]

The PRIUS+ Project run by CalCars made the first conversion of a Toyota Prius to plug-in,^[190] and also offers conversion instructions for do-it-yourselfers.

Awards

• 1997–98 Car of the Year Japan^[191]
• 2003 Scientific American names Toyota Motor Corporation as "Business Leader of the Year" ("Scientific American 50"; December, 2003) for its singular accomplishment in the commercialization of affordable hybrid cars.
• Motor Trend Car of the Year, 2004^[26]
• Car and Driver magazine's Ten Best list for 2004.
• North American Car of the Year award for 2004. Nominated in 2001.
• International Engine of the Year for 2004.
• "Best Engineered Vehicle for 2004" by SAE's Automotive Engineering International magazine.^[192]
• 2005 European Car of the Year (406 points, ahead of Citroën C4 with 267 points and Ford Focus II with 228).^[193]
• 2006 EnerGuide Award (Midsize)^[194]
• 2006 Intellichoice Best Overall Value of the Year, Midsize^[195]
• 2007 Intellichoice Best in Class Winner :Best Retained Value, Lowest Fuel, Lowest Operating Costs, Lowest Ownership Costs^[196]
• Swiss government named Toyota Prius the world's greenest car in a draft study of over 6,000 cars.^[197]
• Green Engine of the Year 2008 from International Engine of the Year Awards.^[198]
• 2008 Nominated for WhatGreenCar.com Car of the Year Awards 2008, shortlisted for the UK's top Green Car Awards
• JD Power and Associates "Most Dependable Compact Car" for 2008^[199] and 2009^[200]
• 2009 Japan Car of the Year^[201]
• ABC News Top 10 Innovations of the Decade^[202]
• 2010 Best Hybrid Car for the Money, U.S. News & World Report^[203]
• RevvItUp The Car Blog's Car of the Decade
• 2010 MotorWeek Drivers' Choice Best Vehicle of the Year^[204]
• Selected among Kelley Blue Book Top 10 Green Cars for 2010^[205][206]

Competitors

• The 2009 (MY 2010) Honda Insight is a compact that emphasizes affordability.^[207] The Honda Insight, billed as the cheapest gasoline-electric hybrid on the market, ranked as the top-selling vehicle in Japan for April 2009—the first time a hybrid has clinched that spot.^[208] When the Prius launched in May 2009 it took Japan's top spot while Insight sales fell to third.^[209] Features such as 15" alloy wheels, 6-speaker audio, cruise control and electronic stability control while standard on the US-spec Prius II (MSRP US$22,000) are optional on the Insight.

• 2001–2005, and 2005–present Honda Civic Hybrid, a derivative of the standard Civic sedan model, equipped with a hybrid gas-electric powertrain.

• 2009 (MY 2010) Ford Fusion Hybrid, to compete against the 2009 (MY 2010) Prius IV and V

See also

• ACT Hybrid Vehicle Authority
• Chevrolet Volt
• Comparison of Toyota hybrids
• Fuel economy-maximizing behaviors
• Hybrid electric vehicle
• Hybrid Synergy Drive
• Hypermiler Driving (drivers who exceed EPA estimated MPG)
• List of hybrid vehicles
• Plug-in hybrid electric vehicle
• Toyota Camry Hybrid
• Toyota eCom
• Toyota FT-CH Concept
• Toyota Prius Custom Plus Concept
• Toyota Prius Plug-in Hybrid

Notes and references

External links

• Official Toyota Prius website- US(English)
• Official Toyota Prius site – UK (English)
• Official Toyota worldwide website
• Toyota Prius at the Open Directory Project
• Toyota will launch series production PHEV Prius in 2012
• How it Works (use left sidebar to read the topics)