A Gleichmäßigkeitsprüfung (abbrev. GLP, German for regularity test) is a motorsport event where precise timing is winning, not outright speed.
Mainly Classic cars events like the modern Mille Miglia are held as GLPs.
A special GLP series is held at the Nürburgring, on the 20.832 km long Nordschleife. On seven Saturday mornings, between 9:30 and 13:00, about 100 regular road legal cars take part, each carrying a driver and a co-driver, both fitted with helmets. They have to do 12 laps (250 km in total), with lap times in the range of 10 minutes to 15 minutes, or average speeds between 125 km/h and 83 km/h.
Each team can set its own target times twice, which has to be repeated three times each, for a total of 8 laps counting towards the results. The remaining four laps are in-lap, two pitstop laps, and out-lap. Time is measured in 1/100 seconds, and results are given in 1/10 seconds. Winners typically accumulate about 4 points, or 0.4 seconds, which means they cross the start/finish line with a precision of about 5/100 of a second for each of eight laps. Top-10-finishers manage about 1/10 sec, midfield-finishers about 1/2 to 1 second or more per lap.
Stopping or very slow driving is not permitted within 1 km of the start/finish line, but there is a "waiting zone" on the very long and wide straight called "Döttinger Höhe". Thus, competitors can drive for about 20 km as they like, enjoying the famous Green Hell of the Nordschleife while track marshalls provide similar security as in races (unlike in the public access hours).
Co-drivers are a vital part of the success, as they usually do the timing, guiding the driver to the finish line with 1/10 sec precision or better. Some co-drivers get sick during the 2 or 3 hours of driving, though.
The entry fee including the one-event competition license is about 200 Euro. Due to insurance issues and the event being designated as National, the cars have to be registered in Germany, and the competitors need an address in Germany, too. Occasionally, foreign race drivers are allowed to take part, mainly to prepare for the 24 Hours Nürburgring, e.g. actor Robert Carradine in 2001, or Italian lady racer Tamara Vidali.
A related event, with race cars and emphasis on outright speed, is the Rundstrecken Challenge Nürburgring (Castrol-Haugg-Cup, CHC), which is usually run by the same organizers in the afternoon following a GLP, but also on separate occasions on different race tracks.
| Date | Organizers |
|---|---|
| 29.04.2006 | Scuderia Augustusburg Brühl |
| 10.06.2006 | MSG Solingen |
| 15.07.2006 | MIG 7 |
| 05.08.2006 | SFG Schönau |
| 02.09.2006 | mc roetgen |
| 07.10.2006 | BMC Wuppertal |
| 21.10.2006 | Automobil-Club Altkreis Schwelm |