• Highway traffic laws are intended to make travel safer.automobiles on the west side highway image by Jorge Moro from Fotolia.com
  
  The beginning of the 20th century saw passage of highway traffic laws. New York State converted laws regulating carriages to "automobiles or motor vehicles and all other vehicles propelled by electricity, steam, gasoline or other source of energy," but it wasn't until 1924 that drivers were required to obtain a driver's license to take these vehicles out on the road. As traffic increased, laws were passed to regulate the traffic and keep drivers relatively safe.
  
  

Traffic Signals

• The first traffic signal was placed in London in 1868, according to the Technology Transfer Program at the University of California, Berkeley. Ironically, the semaphore light was installed to control horse and pedestrian traffic. Early traffic lights operated by human manipulation. As auto traffic expanded, the signals and the police officers operating the signs were given tall stands or booths on the streets to lift the lights above the traffic so all could clearly see the directions. Signals limit the entrance into the intersection only with the green light. The traffic code forbids entrance into the intersection on yellow or red light. Traffic signals with red, green and yellow lights were standardized throughout the U.S. in 1935.
  
  

Farm Equipment

• States with large amounts of farming regulate the use of farm equipment on highways. Even large freeway systems in California post signs forbidding tractors and other farm equipment from entering the major roadways. Most small Midwestern towns regulate farm equipment to rural roads, but some allow large combines to take the main streets of the tiny towns. The U.S. Department of Agriculture in 2009 reported that national committees were established to make recommendations for uniform regulation of farm equipment on public roads and make improvements to the safety of the equipment for travel.
  
  

Speed Limits

• Despite the fact that the majority of roads were rural and that the U.S. didn't construct an interstate highway until the Eisenhower Administration in the 1950s, speed limit laws were first implemented in the early 1900s. The Indiana General Assembly in 1905 set limits at 8 mph for municipalities, 15 mph for areas outside the business districts and 20 mph for any other roads. State legislatures set current speed limits for state roads, and municipalities decide limits within the city and county. Federal funding, such as highway funds, stipulate speed regulations attached to the money, but states can decline to accept the funding to assign higher speeds.
  
  

Seat Belt Use

• The National Traffic and Motor Vehicle Safety Act, passed by the federal government in 1966 set national standards for motor vehicles and recommended state programs including licensing requirements, traffic control and enforcement suggestions. The law eventually mandated installation of seat belts, padded dashboards and windshield wipers, but the states controlled mandating use of the belts. California passed a mandatory seat belt laws for drivers in 1986 and by 2008 approximately 83 percent of drivers used the belts, according to the National Highway Traffic Safety Administration.