The article "Vehicle-Arrival Characteristics at Urban Uncontrolled Intersections" (V. Rengaraju and V. Rao, Journal of Transportation Engineering, 1995: 317-323) presents data on traffic characteristics at 10 intersections in Madras, India. At one particular intersection, the average speed for a sample of 39 cars was 26.50 km/h, with a standard deviation of 2.37 km/h. The average speed for a sample of 142 motorcycles was 37.14 km/h, with a standard deviation of 3.66 km/h. Find a 95% confidence interval for the difference between the mean speeds of motorcycles and cars.