Law enforcement officers and first responders at the national, state and local levels are urging Congress to reject proposals for heavier and longer trucks. They base their opposition to bigger trucks on years of professional training and real-world experience in commercial vehicle enforcement and crash investigations. Below are the key safety factors they emphasize as the basis for their opposition to bigger trucks.
Higher Crash Rates
The 2016 USDOT Final Report to Congress (Table 2, pg. 10) found that heavier trucks have alarmingly higher crash rates compared to 80,000-pound, single-trailer trucks:
- 47 percent higher crash rates in Washington state (91,000 pounds)
- 99 percent higher crash rates in Idaho (97,000 pounds)
- 400 percent higher crash rates in Michigan (97,000 pounds)
The 2000 USDOT Comprehensive Truck Size and Weight Study (vol. 3, pg. VIII-5) found that multi-trailer trucks have an 11 percent higher fatal crash rate than single-trailer trucks.
More Severe Crashes and Larger Crash Footprint
- The severity of a crash is determined by the velocity and mass of a vehicle—if weight increases, so does the potential severity of a crash. Any increase in crash severity increases the likelihood of injuries becoming more serious, or resulting in fatalities.
- Double 33s will have a larger crash “footprint” when involved in an accident.
More Braking Problems and Longer Stopping Distances
- USDOT found in its 2016 report (Table 2, pg. 10) that trucks weighing over 80,000 pounds had 18 percent higher braking violation rates compared to those at or below 80,000 pounds. This is especially important because a 2016 study by the Insurance Institute for Highway Safety found that trucks with any out-of-service violation are 362 percent more likely to be involved in a crash.
- USDOT also found that Double 33s take 22 feet longer to stop than the current Twin 28s and 17 feet longer than the current 53-foot singles (2015 Highway Safety and Truck Crash Comparative Analysis Technical Report, Table 26, pg. 65).
Greater Risk of Rollover, Poorer Handling, and Compromised Emergency Maneuver
- Heavier trucks tend to have a higher center of gravity, which increases the risk of rollovers (2000 USDOT Comprehensive Truck Size and Weight Study).
- Adding an axle to a trailer decreases the steerability of a truck (2000 USDOT Comprehensive Truck Size and Weight Study).
- USDOT found in its most recent study that Double 33s experienced poorer performance compared to the current Twin 28s in avoidance maneuvers, and during certain scenarios were “on the verge of instability” and more likely to roll over (2015 Highway Safety and Truck Crash Comparative Analysis Technical Report, pgs. 72-74).
Difficulty Passing and Merging, Dangerous Speed Differential and Larger Blind Spots
- Heavier trucks accelerate more slowly and have difficulty maintaining speed on upgrades, increasing speed differentials with other traffic and increasing the risk of accidents.
- Longer trucks create larger blind spots behind and beside the truck, increasing the risk of lane change-related collisions.
- Longer trucks take longer to pass, and are more dangerous on two-lane roads.