Assume you are an observer standing at a point along a three-lane roadway. All vehicles in lane 1 are traveling at 25 mi/h, all vehicles in lane 2 are traveling at 40 mi/h, and all vehicles in lane 3 are traveling at 55 mi/h. There is also a constant spacing of 0.5 mile between vehicles. If you collect spot speed data for all vehicles as they cross your observation point, for 30 minutes, what will be the timemean speed and spacemean speed for this traffic stream