Evaluation of the MAG Safety and Elderly Mobility Signs Project

NOTE: On March 28. 2018, the Federal Highway Administration (FHWA) issued a reinstatement of IA-5, Interim Approval for Use of Clearview Font for Positive Contrast Legends on Guide Signs. On January 25, 2016, FHWA had announced the termination of the Interim Approval, that was issued on September 2, 2004. On December 13, 2016, FHWA issued a Request for Information related to use of Clearview font. The response submitted by MAG is available under Materials.

In 2007, the MAG Transportation Safety Committee and the MAG Elder Mobility Stakeholders Group jointly launched a road safety project aimed at improving the road environment for older road users. The project installed street name signs designed for better legibility, based on the FHWA Guidelines and Recommendations to Accommodate Older Drivers and Pedestrians. The types of signs installed by the project included: street name signs, advance street name signs, and internally illuminated signs, with most of them using larger Clearview font.  The project spent a total of $300,000 , in regional funds, supporting the full cost of producing the new signs with the local agencies responsible for all installation costs. The project also provided participating local agencies that had sign fabrication  shops, with the required software for producing signs with Clearview font.

A total of 15 local jurisdictions in the MAG region participated in the project.  Project funds were distributed based on the older population in each jurisdiction.  A total of 2700 signs were installed by the project  across the region.

Signs with Clearview font

A study was launched to evaluate potential safety benefits to road users from these new  signs with Clearview font.  The study was performed for MAG, by a research team from the Arizona State University led by Professor Robert Gray.  The objective of the study was to develop a sound analytical approach to quantify the mobility and safety impacts of the new signs, with Clearview font, installed at various intersections across the MAG region.  Although Clearview font has been shown to improve simple detection and legibility, no studies had been conducted to directly measure the effect of Clearview font on driving performance. Improved legibility is not always predictive of performance in more complex driving tasks and of driving safety in general (Wood & Owens, 2005).  The primary goal of this study was to investigate the effect of Clearview font signs on safety and mobility in a simulated driving and navigation environment.

Driving simulation study of signage fonts

In this study, 36 drivers ranging in age from 56-70 years were asked to navigate through a virtual city in a driving simulator.  Their driving performance was compared for, signs with Clearview and Standard font, and for overhead and advance intersection signs under simulated day and nighttime driving conditions.  Consistent with similar previous research the study found that the distance at which drivers could accurately recognize street names was consistently and significantly greater for Clearview font signs.  The increase in sign recognition distance associated with Clearview font ranged between 8 - 34ft across the drivers in this study with an average increase of 14ft.  Expanding on previous research in this area, the study team also found that the usage of the Clearview font was associated with consistent and statistically significant improvements in several measures of driving safety.  With Clearview signs, drivers in the study made 52% fewer turn errors, changed lanes for an upcoming left turn at a significantly greater distance (by 5.2 ft on average) from the intersection (indicative of better anticipation and planning) and drove at a speed closer to the designated speed limit (change in speed of 3.2 mph on average).  The study also observed fewer collisions with other vehicles when Clearview signs were used.  All of these variables are indicators of improved safety and mobility for elderly drivers.

Interestingly, drivers' subjective evaluations of the effectiveness of Clearview signs did not match perfectly with the results for driving performance.  Clearview signs were rated as significantly easier to read (ratings were 5% higher on average) but the magnitude of the effect was much smaller than the effect sizes for the driving performance variables and for sign recognition distance.  Furthermore, 33% of the drivers in the study indicated that the signs with Standard font were easier to read than signs with Clearview font, when asked to make a forced choice between the two signs. This occurred even though 100% of the participants in the study actually drove more safely in the simulated environment with Clearview signs. Therefore, the measured improvements observed in driving safety are much greater than one might predict from making a subjective judgment about the signs.  This study indicated that this will be an important point to emphasize when local agencies need to justify funding to support Clearview sign adoption.

Based on the significant improvements in driving safety and mobility identified, the  study recommended that the Maricopa Association of Governments continue to encourage local agencies to adopt the Clearview font for street name signs.  As a direct result of the MAG project that helped install 2700 new signs, a number of local agencies have adopted the use Clearview font on all new street name signs.