Discription of Events: The Dark Green 2006 Buick LaCrosse was observed traveling along West University Drive in Tempe, Arizona, 85281. The incident occurred between 9:45 P.M. to 10:10 P.M. Arizona Time on November 16th, 2018 on West University Drive just before the intersection at South Priest Drive. Possible VIN number is 2G4WE587961117241. I observed the vehicle accelerating faster than the speed that I was traveling at and the driver of the vehicle behind me tailgated me and followed behind me too closely. I was about to slow down to a red at South Priest Drive in Tempe when the light turned green and I accelerated. Then, I observed the driver of the Buick Lacrosse passing me and accelerated beyond the posted speed limit. The vehicle was speeding and exceeded the speed limit.