and 9% for suspected criminal activity. 7% of killings by police started with a traffic stop. Two thirds of killings by police started with no crime or a nonviolent crime. Jurisdictions can still use traffic cameras, send tickets in the mail and can pull the car over and send a text message if both driver & police agency sign up for the service. 75% of police have not received recent hands-on training in removing a noncompliant person from a vehicle. Noncompliance was most common in cases of alcohol, drugs or illegal activity, and 42% of noncompliance involved disobeying the officer, while 24% involved not answering the officer' questions, a practice recommended by lawyers. Some North Carolina cities encouraged drivers to refuse searches by requiring the officer to get a signed form, which clarified the voluntary nature of searches. Some departments have quotas for at least a minimum number of traffic stops per officer per month, or supervisor pressure. Stanford has compiled data on racial disparities in 200 million traffic stops. Stops are particularly common and harmful for minorities. Illinois in 2016 found contraband in one stop per 242. In July 2021 a study found that State patrol traffic stops were not associated with reduced motor vehicle crash deaths and suggested other strategies such as motor vehicle modifications, community-based safety initiatives, improved access to health care, or prioritizing trauma care as other reduction efforts. France, England and Wales use traffic stops at a quarter to a third of the US rate. Table of state & local practices Legal basis for stops In the United States, traffic stops have been criticized for their use in police dragnets to check compliance with laws such as those requiring the use of seat belts or those prohibiting driving while impaired. Some people have objected that the tactic violates the United States Constitution; the Fourth Amendment to the Constitution, part of the Bill of Rights, contains a provision against unreasonable search and seizure. However, the United States Supreme Court has ruled that a motor vehicle is subject to a diminished expectation of privacy as compared to a home. Reasons include the fact that motor vehicles are typically driven on public streets, that said vehicles are generally subject to public licensing and registration requirements, and that said vehicles are generally held out to public view in a way different than that of traditional dwellings. In Delaware v.