ANALYSIS OF CAPITAL BELTWAY CRASHES: YEARS 1993-1996

The 64 mi (103 km) interstate highway system encircling Washington, D.C. is known as the Capital Beltway. Hardcopy crash reports for all crash events occurring on the Capital Beltway during the period 1993 through 1996 (N=9,403) were provided by Maryland and Virginia. From 1993 to 1996 total crashes decreased per million vehicle miles traveled (from .45 to .43); injury/fatal crashes decreased (from .19 to .18); alcohol related crashes decreased as a proportion of total crashes (from 8.1% to 6.8%) and fatal crashes dropped by nearly half (from 17 to 9). Crash type distribution remained relatively consistent over time. Three major crash types accounted for 78% of all crashes. The most common type of crash was "stop/slowing" (36% of all crashes). Congestion was typically a factor in these crashes. "Ran off road" was second (24.3%) and "sideswipe/cutoff" was third (17.8%). Tractor-trailers remained relatively consistent as a proportion of total vehicles in crashes. The number of crash involved straight trucks increased.