Traffic signals are often seen by the public and elected officials as a cure-all for operational and safety problems at intersections. Although signals have been used for many years, very little is actually known about their impact on safety. The Crash Experience warrant in the Manual on Uniform Traffic Control Devices (MUTCD) (one of eight warrants that set minimum thresholds for considering installation of a traffic signal) is not well supported and does not consider crash severity. The MUTCD specifies that an engineering study "should indicate a traffic signal will improve the overall safety and/or operation of the intersection" before a signal is installed; however, there are no tools to help the traffic practitioner determine the likely impact on safety from installing a traffic signal. Past studies have yielded contradictory results and suffered from a number of serious deficiencies. Sometimes changes in traffic conditions can eliminate the need for an existing traffic signal. Practitioners need a way to analyze the safety impact of removing such a signal. This information can be used to alleviate the public concern that usually blocks signal removal.