Brake assist systems that automatically apply full braking power for emergency stops might become mandatory on all new cars starting in 2008.
The active safety measure is part of a draft proposal to change phase two of the European Union's pedestrian safety rules.
According to the draft, which was issued by European Commission officials, a study has found that meeting phase two requirements is "not technically feasible."
Automakers also might be allowed to fit cars with active collision avoidance systems to help reduce pedestrian injuries.
"We always said active safety is better than passive," said Alfredo Filippone, spokesman for the European automakers group, ACEA. "It's better to try to avoid the collision in the first place."
The deadline for comment on the draft was last Friday (July 22).
Phase one pedestrian safety rules take effect October 1, 2005 and phase two starts September 1, 2010. The draft doesn't suggest any change to phase one rules.
Both phases require carmakers to change the designs of car front ends to allow more crash-absorbing crush space between the hood and so-called "hard points" such as the engine and radiator.
Feasible safety gain
A Commission insider said a study carried out last year showed adding brake assist and then offering the prospect of using active collision avoidance systems would make meeting phase two of the directive "a more feasible proposition" for the automakers without reducing expected safety benefits.
The problem is that no collision avoidance system is reliable enough today to replace passive safety designs intended to make car front-ends less damaging to pedestrians.
But suppliers such as Germany's Siemens VDO Automotive say successful systems that see an object, determine the driver won't stop quickly enough and activate the brakes are only a few years away.
Siemens VDO spokesman Enno Pflug concedes that "an object detector needs a lot of computing power to detect a pedestrian."
Brake assist technology is already on the market. A Robert Bosch radar-based system is now available on the Audi A6 and A8. The supplier has promised that by late 2006 it will have a system that gives a strong jolt to the brakes to warn the driver that immediate braking is needed to prevent a crash.
DaimlerChrysler welcomed the potential changes to the safety rules, D/C spokesman Matthias Brock said. The German-US automaker has lobbied hard for brake assist.
Toyota Europe spokesman Colin Hensley said the company would introduce active systems when possible regardless of legislation.