<P> Traditionally, intentional contact between vehicles has been characterized as unlawful deadly force, though some U.S. federal appellate cases have mitigated this precedent . In Adams v. St. Lucie County Sheriff's Department, 998 F. 2d 923 (11th Cir. 1993)., the Seventh Circuit Court of Appeals ruled that although fatalities may result from intentional collisions between automobiles such fatalities are infrequent, and therefore unlawful deadly force should not be presumed to be the level of force applied in such incidents; the Adams case was subsequently called into question by Harris v Coweta County, 406 F. 3d 1307 (11th Cir. 2005)., which in turn was reversed by the U.S. Supreme Court in the Scott v. Harris case discussed above; the extent to which Adams can continue to be relied on is uncertain . In the Adams case, the officer rammed the suspect's vehicle . </P> <P> In Donovan v. City of Milwaukee, 17 F. 3d 944 (7th Cir. 1994)., the Seventh Circuit Court of Appeals recognized this principle but added that collisions between automobiles and motorcycles frequently lead to the death of the motorcyclist, and therefore a presumption that unlawful deadly force was used in such intentional collisions is more appropriate . In the Donovan case, the suspect lost control of his motorcycle and became airborne, crashing into the officer's vehicle, which was parked as part of an intercepting roadblock . </P>

When are police authorized to use deadly force