Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
Automated Enforcement (Speed, red-light, Toll, HOV)
• Safety: The installation of speed enforcement cameras in the UK led to a decrease in casualties by an average of 28 percent (56).
Research that analyzed data for all injury accidents in Cambridgeshire in southeastern Britain between 1990 and 2002 indicated
that the installation of a speed limit enforcement camera can be expected to lead to decreases in injury accidents by 45 percent (56).
Research conducted by PA Consulting Group and University of Liverpool showed that there was a 22% reduction in personal
injury collisions (PICs) at sites after cameras were introduced. Overall 42% fewer people were killed or seriously injured. At
camera sites, there was also a reduction of over 100 fatalities per annum (32% fewer fatalities) (57).
Research regarding automated speed enforcement in Montgomery County, Maryland indicated that the proportion of drivers
traveling more than 10 mph above posted speed limits declined by about 70% at locations with both warning signs and speed
camera enforcement, 39% at locations with warning signs but no speed cameras, and 16% on residential streets with neither
warning signs nor speed cameras (58).
• Mobility: A survey of I-30 motorists (a facility with HOV lanes) in 1995 determined that the transit users perceived travel time
savings as 13 minutes during the AM peak and 12 minutes in the PM peak. The I-30 carpoolers perceived they save 16 minutes
during the AM peak and 13 minutes in the PM peak over the general-purpose lanes (60).
Travelers saved about 20 minutes per trip on HOT lanes on I-10 in Houston (61).
In Southern California, SR-91 customers estimated they saved nearly 30 minutes during their morning and afternoon commutes
(61).
Average speed during the AM peak on the Katy Freeway in Houston, Texas was 25 mph on the general purpose lanes and 59 mph
on the HOT lanes (61).
• Efficiency: A four year research conducted by PA Consulting Group and University of Liverpool showed that after speed and redlight
cameras were introduced there was a positive cost-benefit of around 2.7:1. In the fourth year, the benefits to society from the
avoided injuries were in excess of £258 million compared to enforcement costs of around £96 million (57).
One study of British Columbia’s automated speed enforcement program examined the avoided costs of speeding-related fatalities
and injuries and concluded that it produced annual savings of over 38 million Canadian dollars (59).
Bus operating speeds have more than doubled since the opening of the HOV lanes on I-30 and I-35E North during the AM and PM
peak hour, and because of the time savings the operating cost of DART buses using the lane has been reduced by approximately
$350,000 per year (60).
ADDITIONAL DESCRIPTION AND QUANTITATIVE BENEFITS OF TRAVEL-TIME RELIABILITY STRATEGIES Page F-20