The German motorsport authority DMSB has sealed four DTM cars which will be analyzed and used as the references for the championship's development freeze.
Last weekend's race at the Nurburgring was the last opportunity for Mercedes and Audi to add any updates to their cars, with development now being frozen until the end of 2010.
After the race, the DMSB sealed the 2009-spec cars of Timo Scheider and Bruno Spengler, and the 2008 models of Mike Rockenfeller and Jamie Green. The details of those cars will now form the reference criteria from which the freeze will be enforced for the next year and a half, before the series introduces its new technical regulations for 2011.
Hans Werner Aufrecht, boss of series promoter ITR, said: "I appreciate the decision made in co-operation with DMSB to do without expensive new developments for 2010 and to contest the coming season with the vehicles that have been raced this year.
"With its thrilling races, the current season has demonstrated the extreme competitiveness of the cars entered by Audi and Mercedes-Benz, the two manufacturers entered in DTM."
Teams will still be allowed to go testing as before outside of race weekends, although only to fine-tune setups rather than work on development.