November 15, 2005
TRUCKS-SPEED LIMITS AND LANE RESTRICTIONS
By: Kevin E. McCarthy, Principal Analyst
You asked whether (1) Germany or other European counties impose lower speed limits on trucks or limit trucks to a single lane on expressways and (2) any American states or the federal government have considered such limits.
Germany and other European countries have expressway speed limits for trucks that are substantially lower than the limits for cars. They often limit trucks to a single lane.
Eleven American states have lower expressway speed limits for trucks than for cars, although the difference in the limits is far smaller than in Europe. Georgia, Indiana, and Massachusetts require that trucks on expressways drive in the furthest right lane, except when passing or under certain other circumstances. Virginia has a similar provision. Several other states have considered such restrictions.
We are not aware of any federal initiatives to establish a different speed limit for trucks and cars or to limit trucks to a single lane when driving on expressways.
GERMANY AND OTHER EUROPEAN COUNTRIES
In Germany, most trucks are limited to 80 kilometers per hour (kph, the equivalent of 48 miles per hour or mph) on the Autobahn network. The 80 kph limit also applies to buses and cars pulling trailers. In contrast, most of the network has a recommended, as opposed to mandatory, speed limit of 130 kph (81 mph) for cars and motorcycles. Approximately 40% of the network, notably in urban areas, has mandatory speed limits for cars and motorcycles of 80 to 120 kph (50 to 75 mph). Substantially different expressway speed limits for trucks and other heavy vehicles on one hand and cars on the other are common in Europe, generally 80 to 90 kph for the former and 120 to 130 kph for the latter.
In Germany and other European Union counties, trucks with a gross vehicle weight rating of 3.5 tonnes (7,700 pounds) or more must have a governor that limits their speed to 90 kph (54 miles per hour). This requirement also applies to buses with more than 8 passenger seats whose maximum weight exceeds 10 tonnes (22,000 pounds).
Trucks in Germany and other European Union countries are often restricted to the right lane. In addition, traffic laws require vehicles to keep to the right except when passing. Since much of the expressway network throughout Europe is two lanes in each direction, this requirement combined with the lower speed limits for trucks tends to restrict trucks to the right lane as a practical matter.
A number of states have established different speed limits for trucks and cars on expressways, although the difference is generally much smaller than in Europe. For example, in 1996, Arkansas raised the speed limit for cars from 65 to 70 mph while keeping a 65 mph limit for trucks. In 1998, Idaho changed from a uniform speed limit of 75 mph for all vehicles to a 65 mph limit for trucks. In contrast, in 1994 Virginia switched from a speed limit of 65 mph for cars and 55 mph for trucks to a uniform limit of 65 mph for all vehicles. According to the National Conference of State Legislatures, 11 states currently have differential speed limits for rural interstate highways: Arkansas, California, Idaho, Illinois, Indiana, Michigan, Montana, Ohio, Oregon, Texas, and Washington. Texas also has differential limits for urban interstate highways and other limited access roads.
In 2004, the Federal Highway Administration (FHWA) studied the impacts of differential speed limits in the United States. It found that, except for Virginia, average speeds tended to increase over the 1990s regardless of whether the state maintained a uniform limit or differential limit or changed from one to the other. In some cases the increase in speed was significant, in other cases it was not. It also found no consistent safety effects of one type of limit over the other. It found that states with differential limits had 26% higher rate of car-into-truck rear-end accidents compared to states with uniform limits. Conversely, states with uniform limits had higher levels of truck-into-car rear-end accidents (57%), sideswipe accidents (41%), and other vehicle collisions (103%) by comparison. Crash rates tended to increase over the 10-year study period, regardless of whether there was a uniform or differential speed limit. The study is available online at http://www.tfhrc.gov/safety/pubs/04156/.
A 2005 report by the Wyoming Legislative Service office provides information on studies conducted by the states of Idaho, Oregon, and Virginia. The Wyoming report concludes, based on the federal and state reports, that the costs and benefits of differentiated speed limits cannot be definitively determined. The Wyoming report is available online at http://legisweb.state.wy.us/PubResearch/2005/05IB002.pdf.
Connecticut bars trucks from the left lane of expressways with three or more lanes in one direction in most circumstances (CGS § 14-230a). It also requires trucks with oversize permits to drive on the right lane of expressways under most circumstances (CGS § 14-230). A number of other states have similar laws. For example, Michigan, Rhode Island, Utah, and Washington require trucks and certain other vehicles to drive in the right two lanes of an expressway that has three or more lanes in one direction.
Georgia, Indiana, Massachusetts, and Virginia have more stringent requirements. Georgia bars trucks from driving in the left hand lane of a road or highway that has two lanes in each direction, except to pass, make a left turn, or under other limited circumstances (Ga. Code. Ann. § 40-6-52). Indiana requires trucks to use the far right lane on interstate highways except when passing, when entering or leaving a highway, or where a special hazard exists that requires the use of another lane (Ind. Code § 9-21-8-12). Massachusetts requires that trucks over 2.5 tons to use the far right lane on expressways with three or more lanes in each direction, except when passing or in an emergency. When passing, the truck must use the next lane (Mass. Gen. Laws. § 89.4C). Virginia generally bars trucks from driving in the left hand lane on interstates with three or more lanes. In addition, if a truck is driving at a speed that is 15 or more miles per hour slower than the posted speed on an interstate that has two lanes in each direction, it must stay in the right hand lane (Va. Code § 46.2-803.1). Legislation imposing similar requirements has been considered in several other states, including Alabama, Kentucky, Maine, Missouri, Nevada, South Carolina, and Tennessee.