6.5 There are 240 automobile drivers per minute who are considering using the E-ZPass lanes of the Interstate 78 toll bridge over the Delaware River that connects Easton, Pennsylvania, and Phillipsburg, New Jersey. With that many autos, and a 5 mph speed restriction through the E-ZPass sensors, there is congestion. We can divide the drivers of these cars into groups A, B, C, and D. Each group has 60 drivers. Each driver in Group i has the following value of crossing the bridge: vi if 60 or fewer autos cross, vi - 1 if between 61 and 120 autos cross, vi - 2 if between 121 and 180 autos cross, and vi - 3 if more than 180 autos cross. Suppose vA = $4, vB = $3, vC = $2 and vD = $1. The marginal cost of crossing the bridge, not including the marginal cost of congestion, is zero.