A recent "Did You Know" article explained the Federal "Manual of Uniform Traffic Control Devices," where signs, signals, pavement markings and other devices used to regulate, warn or guide traffic are controlled by federal standards, creating uniformity across the nation. However, states are left to set vehicle and traffic (V&T) laws within each state. This results n a wide variation of V&T laws from state to state.
For instance, in New York state, the law requires a driver to signal a turn or a lane change at least 100 feet prior to the turn or lane change. In Indiana, signaling a turn or lane change is required 200 feet prior, and if the speed limit is 50 mph or more, signaling is required at least 300 feet before turning or changing lanes.
Another examplem - on highways having dual or multiple roadways separated by safety islands or physical traffic separation installations (divided highway), it is illegal to pass a stopped school bus on the opposite highway in New York state, whereas in New Jersey, the driver must reduce the speed to not more than 10 mph, but is not required to stop.
There are hundreds of examples where V&T laws vary widely from state to state. Perhaps these variations didn't mean much 75 years ago, when there was very little driving from state to state, but today, with our very mobile society, we need more uniformity in V&T laws throughout the nation, similar to the uniformity in traffic control devices.
Another area now being considered for federal regulation is graduated licensing, where teen drivers are granted more driving privileges over time, aimed at lowering the risks teens face during their early years on the road. Graduated licensing varies widely from state to state. Further, surveys show that parents are in favor of higher licensing ages and stricter limitations to teen drivers than are the norm in United States. If enacted, the federal government would establish a minimum guideline for states' graduated licensing system. This bill would provide for monetary incentives to states that enact the basic tenets and would withhold some federal funding to states that don't comply.
In my (author of the "Did You Know" articles) opinion, we need to go further. We need to standardize the basic V&T laws throughout the nation, so the distance required for signaling is the same in all states, or the laws governing how motorists treat a stopped school bus are the same.
We also need to use the clout of federal laws to do what individual states cannot or will not do. For example, we need to legislate on the federal level that all vehicles sold in the nation are equipped with daytime running lights, proven to be much safer in nations throughout the world. Passenger restraint laws need to be federalized, as do motorcycle and bicycle helmet laws. Radar detectors need to be banned in all states. Location of headlight switches, windshield wipers, and horns should be the same on all vehicles.
The above is just a sampling of vehicle and traffic requirements that need to be standard nationwide, at least in the opinion of this writer. Will it ever happen? Some of it will, but protection of states' rights runs strong in the US, and this will likely always be a barrier to what could be done in the interest of traffic safety.