Seat belts have been mandatory in cars since 1968, and are fairly standard in modes of transportation from airplanes to carnival rides, but not buses.
Beginning in November 2016, a new federal law will require manufacturers to install three-point-lap-shoulder belts in all new motorcoaches and some other large busses. This rule only applies to busses that provide long-distance service between U.S. cities, such as the Megabus and Greyhound bus lines. School busses and city transit busses are still not required to have seat belts.
This new safety measure is intended to protect the many Americans who choose to travel domestically via motorcoach. Seven hundred million passengers travel on these long-distance coaches annually in the U.S. 21 people die every year from large bus crashes, and nearly 8,000 more are injured. Seat belts could reduce fatalities and moderate to severe injuries by roughly 45 percent.
Passing a rule requiring motorcoaches already on the roads to be equipped with seat belts was rejected due to the excessive cost to manufacturers. Since these vehicles typically operate for 20 to 25 years, it will likely take many years before all long-distance busses in the U.S. have seat belts.
Source: “U.S. to require seat belts on long-distance buses but not city and school buses.” Dallasnews. November 20, 2013.