Project: Criteria for Automatic Illumination of Stop Lamps

Reference: S0020/VD

Last update: 13/03/2008 14:49:39


The objective of this research project is to investigate the effects of automatic stoplamp illumination on driver behaviour and assess whether the wide-scale introduction of this feature could improve road safety.

In achieving this objective the selected Contractor is expected to:
* summarise drivers' understanding of the information provided by illumination of the stop lamp of vehicle(s) ahead and their behaviour in relation to that information;
* describe variables which influence drivers' use of the brakes and other means of deceleration, when confronted with stop lamp activation by the vehicle(s) they are following;
* describe the conditions under which the activation of stop lamps would be of assistance to the following driver;
* establish the various methods of measuring vehicle deceleration and whether instruments of sufficient accuracy are available to measure the deceleration of vehicles in a repeatable and useful way, and their cost;
* establish whether the instruments described above are suitable for fitment to production vehicles. The assessment should take into account normal road variables such as changes in gradient, cornering forces etc;
* establish the highest decelerations available from vehicles on the road today in Western Europe, due to engine braking and similar effects;
* establish the range of decelerations available from devices on the market or close to market readiness (if possible), covering stability control systems, adaptive cruise control, integrated starter generator, regenerative braking, etc;
* propose the circumstances and conditions under which automatic stop lamp illumination should occur that would assist drivers and improve safety in a cost-effective way; and
* establish a simple, inexpensive and repeatable procedure to test vehicles fitted with automatic stop lamps for compliance.

In addition to the objectives listed above, the contractor is invited to consider and propose further ideas that may add value to the research.


Advanced vehicle systems have been developed that either apply the brakes for purposes other than retardation, (e.g. traction control, or stability control systems), or cause a significant deceleration, but without necessarily applying the brakes (e.g. adaptive cruise control or intelligent speed adaptation). With the advent of these modern vehicle control systems, consideration needs to be given to when the following driver ought to be informed that the vehicle is being slowed. If illumination of the stop lamp is not to be reliant upon the operation of the brake pedal, what criteria should be used? The project will help formulate policy in this area and make recommendations for common requirements for the automatic illumination of stop lamps.


TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £350,000.00

Actual start date: 01 November 2002

Actual completion date: 29 July 2005


Criteria for The Automatic Operation of Stop Lamps Vol 1 & 2
Author: TRL
Publication date: 29/07/2005
Source: Published Project Report PPR068 & PPR078, TRL