A controversy over truck speed in Illinois has reignited debate over whether large differentials in truck and car maximum speed limits cause an increase in the number of crashes.

American Trucking Associations and Road Safe America last week sent a letter reminding federal regulators of the need to proceed quickly in developing a proposed rule to require speed limiters on existing and new trucks.

Most freeways in Illinois have a new maximum speed limit of 70 mph as of Jan. 1, the Illinois Department of Transportation reports.

A majority of all drivers support mandating speed-limiting devices on trucks, according to the latest National Highway Traffic Safety Administration survey on driver attitudes and behavior.

An upcoming federal rule mandating speed limiters on heavy-duty trucks will include the requirement that current vehicles be retrofitted as well as new trucks rolling down assembly lines, according to an official of the National Highway Traffic Safety Administration.

The speed limit on 570 miles of rural Ohio interstate highways increased to 70 mph from 65 mph on Monday under a new state law that allows the Ohio Department of Transportation to increase the speed on all nonurban interstates.

The North Carolina House blocked a bill that would have raised top highway speeds to 75 mph in the state, citing safety concerns, the (Raleigh) News and Observer reported.

Researchers at Wayne State University in Detroit have been given a $175,000 grant to study whether different freeway speed limits for cars and trucks make roads safer or more dangerous.

Maine’s Legislature has passed a bill that would authorize the state’s Transportation Department to raise the speed limit to 75 mph on any highway — higher than the 65 mph maximum limit in most of the state — as long as the department concludes that it is a safe speed.