Public reaction to DRLs, generally neutral to positive in Canada, is decidedly mixed in the U.S. Thousands of complaints regarding glare from DRLs were lodged with the DOT shortly after DRLs were permitted on cars, and there was also concern that headlamp-based DRLs reduce the conspicuity of motorcycles, and that DRLs based on front turn signals introduce ambiguity into the turn signal system. In 1997, in response to these complaints and after measuring actual DRL intensity well above the 7,000 cd limit on vehicles in use, DOT proposed changes to the DRL specification that would have capped axial intensity at 1,500 cd, a level equivalent to the European 1,200 cd and identical to the initially proposed Canadian limit. During the open comment period, a volume of public comments were received by NHTSA in support of lowering the intensity or advocating the complete elimination of DRLs from U.S. roads. Automaker sentiment generally ran along consistent lines, with European automakers experienced at complying with European DRL requirements voicing no objection to the proposal, and North American automakers vociferously repeating the same objections they raised in response to Canada's initial 1,500-cd proposal. The NHTSA proposal for DRL intensity reduction was rescinded in 2004, pending agency review and decision on a petition filed in 2001 by General Motors, seeking to have NHTSA mandate DRLs on all U.S. vehicles. The GM petition was denied by NHTSA in 2009, on grounds of severe methodological and analytical flaws in the studies and data provided by GM as evidence for a safety benefit to DRLs. In denying the petition, NHTSA said (…) the agency remains neutral with respect to a policy regarding the inclusion of DRLs in vehicles (…) we do not find data that provides a definitive safety benefit that justifies Federal regulation (…) manufacturers should continue to make individual decisions regarding DRLs in their vehicles.