Retrofitting older vehicles with a collision warning system and a telematics device can significantly improve driver behavior and enhance safety, according to a new study from the Insurance Institute for Highway Safety.

Motorists demonstrated safer driving behaviors across the study period, according to the institute. For example, drivers used turn signals more often and increased following distances after receiving alerts. Speeding, however, did not change dramatically between the baseline and the alert periods.

The findings could be reassuring and serve as an added safety precaution for fleets that rely on older models.

For the study, 22 volunteers signed up to have their personal vehicles outfitted with a Mobileye aftermarket collision warning system, and 17 of them also agreed to have their driving monitored by a Geotab in-vehicle telematics unit.

The Mobileye package featured an in-vehicle display and included forward collision warning; urban forward collision warning, which operates at speeds below 20 mph; pedestrian collision warning; headway monitoring and warning, which measures following distance at speeds above 19 mph; lane departure warning; and a speed limit indicator, which displays the posted speed limit.

The thresholds for triggering the various crash warning alerts were fixed; drivers couldn't disable or customize alerts.

In a post-study survey, some 62% of the volunteers said the Mobileye system helped boost their safety behind the wheel. Drivers evaluated forward collision warning as the most useful system, followed by lane departure warning, headway monitoring and the speed limit indicator.

The study assessed driving behavior over two periods: a four week baseline when the systems were active, but did not issue alerts, and an eight-week period when the crash system alerts were continually issued.

During the baseline period, the telematics devices in equipped vehicles logged GPS locations, hard braking and cornering, travel speed and Mobileye alerts that would have been issued if the system were active.

Volunteers than drove for eight weeks receiving alerts and a weekly Mobileye "safety score."

Key findings include:

• As drivers grew accustomed to the system between the baseline and alert periods, the rate of forward collision alerts decreased 45% among rural drivers and 30% among urban drivers.

• The opposite was true for lane departure warning. Urban drivers saw a bigger decline—70%-- in the rate of alerts than the rural drivers (54%) between the baseline and treatment periods.

• Warnings about following too closely also decreased. Headway alerts fell 63% for rural drivers and 39% for urban drivers between the baseline and treatment periods.

The IIHS points to one study takeaway of particular interest to fleet managers who use aftermarket collision warning systems and telematics devices to monitor driving performance.

"Fleet drivers who travel congested roads would be more likely to encounter situations that trigger forward collision and headway warnings than drivers who log more miles in sparsely populated areas," said Ian Reagan, a senior research scientist with IIHS and the author of the new study. "Their managers should take into account external factors such as traffic density when comparing drivers on safety measures across geographical regions."