(_b_) On longer headways the trolley bus appears to have the advantage due to the lower fixed charges. (_c_) The gasoline bus on account of higher operating expense does not offer competition to the rail car until minimum headways of 10 min. are reached on new routes and 20 min. on existing lines. (_d_) The trolley bus is more economical than the gasoline bus up to headways of 60 min. or longer. A tabulation of the respective fields is as follows: Minimum headways, 3 min. or less; rail cars. Minimum headways, 3 to 6 min.; rail cars or trolley bus. Minimum headways, 6 to 60 min.; trolley bus. Minimum headways, 60 min. or more; gasoline bus. This does not mean that existing lines with headways of 7¹⁄₂ to 10 minutes should be scrapped and replaced with the newer forms of transportation. It would not pay to do this until a headway greater than 15 or 20 minutes has been reached. =Length of Haul for Economical Trucking.=--The railroads would not be alone in the benefits due to better roads. Truck lines could be established to care for freight and passenger traffic between farm and station. Here the truck and railroads would coöperate, there would be no competition, for each would be performing a function incapable (or unprofitable) of performance by the other; the net result would be a benefit to the entire community. But most transport lines that are being established come into actual competition with existing railroad lines. Just how far a motor truck may profitably compete with the railway depends, of course, on the relative costs of transportation. Mr. Cabot[162] calculates that twelve miles is the dividing line between motor truck transport and rail transport. He figures the cost of delivery and removal from the railway station at 15 cents per hundred weight, or $3 per ton at each end for terminal charges and that the cost of motor truck haul is at least 50 cents per ton mile. A ton may be hauled, therefore, on truck, 12 miles to balance the railway terminal expense or charge. A formula might be worked out this way. Let _x_ = the number of miles where rail and truck charges just balance; _m_ = motor truck charge per ton-mile; _r_ = rail charge per ton-mile; _t_ = terminal railroad charge-cost of collecting and delivery to the railroad plus the cost of removal from the railroad. Thus motor charge for _x_ miles is _mx_ and railroad charge for same distance is _rx_ + _t_, equating these, _mx_ = _rx_ + _t_. Solving for the distance traveled, _t_ _x_ = ---------. _m_ - _r_ With Mr. Cabot’s figures this formula gives 6.00 600 _x_ = ---------- = ---- = 13.5. .50 - .055 44.5 Using the cost 25 cents per ton mile made up by actual averages compiled by the Motor Truck Association of America and 5.5 cents used by Mr. Cabot as the railroad cost charge, there results