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Chapter 11 Autos and Highways . Urban Transportation. Three basic problems caused by autos. Congestion What is the optimum level of congestion Pollution Alternative control policies: pollution taxes & gas taxes Highway accidents Can government do anything.
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Chapter 11 Autos and Highways Urban Transportation
Three basic problems caused by autos • Congestion • What is the optimum level of congestion • Pollution • Alternative control policies: pollution taxes & gas taxes • Highway accidents • Can government do anything
What is the Optimal Level of Congestion • Distance of highway is 10 miles • Monetary travel costs are 20¢ per mile • Opportunity cost is 10¢ per minute • Demand for travel: The marginal willingness to pay of the marginal traveler
Congestion Tax • A tax that equals the difference between social trip cost and the private trip cost, will make both costs equal • This tax will reduce the number of trips to the optimum.
Benefits and Costs from a Congestion tax • People who continue using the highway pay the tax, but have lower travel costs • People who stop using the highway do not pay the tax, but forgo the benefits from using the highway • Generates revenue
Efficient Congestion Cast • Taxes may vary between peak and off-peak travel
Responses to Congestion Taxes • Modal Substitution • Time of Travel • Travel Route • Location Choices
Alternative to Congestion Taxes • Gasoline Tax • Increases costs of all automobile travel • Does not encourage changes in time of travel • Parking Tax • Charge different fares parking fares for cars that arrive/leave at different times • Only affects peak period drivers • Does not change travel route or location choices • Only affects cars who park in congested areas • Congestion Zone Taxes
Whathappens if we increase capacity? $ Private Cost Narrow Highway Private Cost Wide Highway Demand Vo Vw Traffic Volume
Subsidies for Transit a) Free Market (B,R) b) Subsidy Transit (S,C) d) Congestion Tax (A,Q); $ Social Trip Cost $ Private Trip Cost Q R A Marginal Social Cost B Private Cost under Subsidy D C S D Sub D Tax D A T
Transit Subsidy (Cont) • A subsidy on transit is less efficient than a congestion tax, because it under prices transit raising ridership above its optimum level
Highway Pricing and Traffic Volume in the Long Run • Government can design a policy with the optimal road volume and the optimal road width? • Derive Average Total Cost Curves • Derive Long Run Average and Marginal Cost Curves (CRS) • Pick the optimum traffic volume and road width • Pick the congestion tax that generates the optimal volume
Average Total Cost Curves • Define ATC=ARC+PTC • There will be an ATC for each size of freeway • U-Shaped because of 2 effects: • Cost Effect • Congestion Effect
Long-Run ATC Curve • For a given volume of traffic, what is the most efficient average total cost? • LRAC envelops the minimum of ATC curves • Long Run Marginal Cost: Long Run Social Cost of an additional driver
Optimum Volume and Road Width • MC=MB • Congestion Tax encourages the drivers to drive a volume of V** • Recall: • ARC=ATC-PTC • Congestion Tax=STC-PTC
Congestion Tax covers the price of the road! • Congestion Tax=Average Road Cost iff Average Total Cost = Social Total Cost • Social Trip Cost is the short run marginal cost of one additional driver • Revenue Sends a signal: • Increase highway size if revenue>ARC
Autos and Air Pollution • Autos and trucks generate air pollution • Externality Problem: Drivers base their decisions to drive or not on the marginal private cost of driving which is less than the marginal social cost of driving
Congestion Tax and the Monocentric City? $ Ro R1 u
Pollution Externalities • Pollution externalities causes: • People drive cars that generate a lot of pollution • People drive too many miles • Solutions: People should pay for the pollution they generate • How to estimate the cost?
What can be done? • One time pollution tax on automobiles that equals the pollution the car generates in lifetime • Use a gasoline tax • Affects all cars, not only the ones who pollute • Reduces pollution be reducing miles driven, not by encouraging people to have cleaner cars
Auto Safety • Auto safety leading cause pf death among 1-24 years old population • 42,000 deaths • Safety Regulations: Air bags, seatbelts, etc… • Theory of risk compensation • Optimum Speed
The value of a life • Ashenfelter and Greenstone (2002) • Use state variations on speed limits to valuate a life. In 1987 21 states moved rural interstate speed limit from 55 mph to 65 mph • Increase of speeds of 3.5% associated with 35% increase in fatality rates • 125,000 hours saved per lost life • Each fatality is valuated in 1.54 million dollars