Before revision:  Under a wage floor on TNC drivers, we consider two schemes of congestion surcharges : (a) surcharge based on each TNC trip , and (b) surcharge based on each vehicle hour (regardless of whether the vehicle has a passenger or not) . We show that both congestion surcharges can reduce the TNC ridership, but their impacts are mitigated by the wage floor and cannot significantly reduce the number of TNC vehicles .
After revision:  Under a wage floor on TNC drivers, we consider two schemes of congestion surcharges : (a) surcharge based on each TNC trip , and (b) surcharge based on each vehicle hour (regardless of whether the vehicle has a passenger ) similar to a road tax. Both charges reduce the number of TNC trips, but this reduction is limited by the wage floor and cannot significantly reduce the number of TNC vehicles .