1) A 2500-pound passenger vehicle originally travelling on a straight and level road gets onto a section of the road with a horizontal curve of Radius=850 ft. If the vehicle was originally travelling at 55 mi/h, determine:
a. The additional horsepower on the curve the vehicle must produce to maintain the original speed,
b. The total resistance force on the vehicle as it traverses the horizontal curve and the total horsepower.
Assume that the vehicle has a front cross-sectional area of 30 ft2.
2) The acceleration of a vehicle takes the form
ƒ
dt
du
3.6 - 0.06u (u is the vehicle speed in ft/sec.)
The vehicle is travelling at 45ft/sec at time To.
a. Determine the distance traveled by the vehicle when accelerated to a speed of 55 ft/sec.
b. Determine the time at which the vehicle attains the speed of 55 ft/sec.
c. Determine the acceleration of the vehicle after 3sec.
3) The design speed of a multilane highway is 60 mi/hr, what is the minimum stopping sight distance that should be provided on the road if:
b. The road is level.
c. The road has a maximum grade of 4 percent.
Assume the perception-reaction time = 2.5 sec.
4) A car hits a tree at an estimated speed of 55 km/h on a 3% downgrade. If skid marks are observed on 35 m of dry pavement (f = 0.45) followed by 75 m on a grassstabilised shoulder (f = 0.20), estimate the initial speed of the vehicle.
5) A temporary diversion has been constructed on a highway of +4 percent gradient due to major repairs that are being undertaken on a bridge. The maximum speed allowed on the diversion is 10 mph. Determine the minimum distance from the diversion that a road sign should be located informing drivers of the temporary change on the highway.
- Maximum allowable speed on highway = 70 mph
- Letter height of road sign = 4 in.
- Coefficient of friction between tires and pavement = 0.2
- Perception-reaction time = 2.5 sec
Assume that a driver can read a road sign within his or her area of vision at a distance of 40 ft for each inch of letter height.