Is it a good idea for two 80,000-pound 18-wheelers to tailgate one another? Many states are considering that issue, due to the emergence of technology designed to make trucks safer, coupled with vehicle-to-vehicle communications. These technologies would allow two digitally-connected trucks to follow each other on the road at a closer distance because the electronically-linked trucks accelerate and brake together, bypassing the driver. This electronic pairing of tractor-trailers is called platooning.

Platooning Saves Fuel

Platooning can save money by reducing fuel costs due to “slipstreaming.” When two trucks pair up closely, the air flows more smoothly with less air drag. A truck in the slipstream of another tractor-trailer can save 10 percent on fuel. The truck in front will also burn about 5 percent less fuel. Buying diesel typically amounts to 20 percent of operating costs, which across the industry runs into billions of dollars.

Is Tractor-Trailer Platooning Legal?

Many states have “following too close” driving statutes that impact platooning. Some states have already exempted platooning from those statutes to allow platooning outright. Others are exempting platooning from the follow-too-close rules to authorize the testing of platooning technology on state roads. A clickable map showing state-by-state rules addressing platooning is available here.

Is Tractor-Trailer Platooning Safe?

Trucks are involved in 11 percent of fatal crashes, although they make up just 4 percent of vehicles on the road, according to the Federal Motor Carrier Safety Administration. Annual crash-fatality data from the National Highway Traffic Safety Administration (NHTSA) indicates that 72 percent of the 4,317 people who died in large truck crashes in 2016 were in passenger cars and 11 percent were pedestrians, bicyclists, road workers, or police officers.

Platooning relies on technologies already installed in some trucks, which must be connected, thus real-time data is a requirement. In digitally-connected trucks, a camera from the front truck displays the road ahead of it to the driver of the second truck. Platooning impacts the ability of drivers to make decisions. A lost connection could impact safety.

Safety advocates are concerned about platooning trucks, according to Jonathan Adkins, executive director of the Governors Highway Safety Association. One issue is how other drivers will react – will they attempt to cut in between the two trucks? Will platoons block exit ramps? The answers to these and other questions remain to be seen.

Researchers at the U.S. Department of Transportation’s Volpe Center studied one issue concerning automated platoons – that is the optimal distance the trucks need to be from one another to maintain safety and still reap the benefits associated with platooning. Based on Volpe’s findings, following distances of approximately one second could minimize crash risk, while preserving the benefits of platooning. That cuts the usual following distance in half. Instead of having two seconds to respond, drivers would have one second. If the lead truck communicates properly, and the following truck responds appropriately, there is no need for the following truck driver to respond at all. However, is one second enough time to respond if something goes wrong in the process?

Two large truck manufacturing companies, Navistar and Daimler, are preparing to put platooning trucks on the road. A California startup company, Peloton Technology, is working with truck makers on its own platooning system. Daimler’s North American truck unit reports that it received permission from the Oregon Department of Transportation to test its platooning technology on public roads. At that point, the real world implications of platooning and its impact on road safety, especially for occupants of passenger cars, will become clear. In hopes, platooning will prove to be safe and innocent motorists will not be injured or killed during the on-road testing.