TRANSPORTATION PLANNING

TOPICS

1. ROADS AND PUBLIC GOODS 2. RATIONALE TO JUSTIFY ROAD BUILDING3. URBAN PLANNING AND TRAFFIC

CONGESTION (UNINTENDED CONSEQUENCES)

4. ROAD BUILDING & MANAGEMENT: THE OLD PARADIGM

5. ROAD BUILDING AND MANAGEMENT: THE NEW PARADIGM

6. MODEL OF URBAN GROWTH AND TRANSPORTATION

TYPE OF GOODS PRIVATE GOOD

– Rival – Exclusion

PURE PUBLIC GOOD OR CPR– Jointly consumed or non rivalry– non-exclusion

TOOL GOODS – Jointly consumed or non rivalry– Exclusion can occur

COLLECTIVE PUBLIC GOODS – Jointly consumed or non rivalry up to a

limit – non-exclusion

Typology of G & S

Individual goods

Toll Goods

con

sum

pti

on

individual

Joint

Feasible Exclusion Infeasible

Commonpool goods

Collectivegoods

Source: E.S. Savas 2000:44-45

Private car

Taxi service

Bus service/Subway

Turnpike Highway City street

RATIONALE TO JUSTIFY ROAD BUILDING

RATIONALERATIONALE IMPACTIMPACT COMMENTSCOMMENTS

Output + Production function in the form of physical capital

Productivity + Real output per unit of labor

Production costs - Elasticity stock of PI (-.05 to -.21)

Property values + and - Negative for CBD

Positive for Suburbanites

Rate of Return + 4.9 to 7.2

Non commercial travel

- Commuting distance increase, opportunity costs (time) increase

URBAN PLANNING AND

TRAFFIC CONGESTION

SHORT-TERM CAUSES – Population and job growth– More intensive use of automobile – Failure to build more roads– Failure to make drivers bear full cost

Source: A. Downs

URBAN PLANNING AND TRAFFIC CONGESTION

LONG-TERM CAUSES – Concentration of work and trips in time – Disconnection between place of work and

residence – Low density development (residence and

work) – Preference of private vehicle over mass

transit system – Urban design/ City planning (middle class

bias)

ACCESS & MOBILITY: THE OLD PARADIGM

• Roads are considered public goods • Solutions came from the supply side • Gasoline tax as a proxy for road pricing • To complex to administer and coordinate efforts

among different levels of government • Disjoint relationship between land use and travel

demand• Problems are taught to be linear

CONGESTIONBUILD MORE ROADS

ACCESS & MOBILITY: THE NEW PARADIGM

• Roads are becoming “toll goods” • Solutions are coming from the demand side

(ability & willingness to pay) • Price system based on marginal cost• Public and private partnership starting to emerge

as well as decentralization of decision making • Land-use and travel demand are part of the

problem as well as the solution (New Urbanism) • Problems are seen as circular with feedback

loops

A SYSTEM MODEL

LOW

LOW

DENSITY

DEN

SITY

DEVELO

PMEN

T

DEVELO

PMEN

T

INCREASE TRAVEL MILE PER VEHICLE

INCREASESROAD

DEMAND

PRIVATEPRIVATETRANSPORTATIONTRANSPORTATION

BUILD MORE ROADS

TRANSFORMLAND USE &

DENSITY

GENERATES MORE ECONOMICACTIVITIES

LAWS OF

LAWS OF

HUMAN

HUMAN

BEHAVIOR

BEHAVIOR

FORECASTING TRAVEL DEMAND

• Four step process 1. Estimating trip generation (HH income, # persons in

the HH, # vehicles, density)

2. Estimating trip distribution (Gravity model): The force of gravitation between two objects is proportional to the product of their masses and inversely proportional to the square of their distance

3. Estimating modal split (private vs. public modes)

4. Trip assignment (distribution of the trips among alternate routes: e.g. how to get to downtown? )

Census Methodology

Origin1,000 trips

Destination A20,000 square feet

Destination C80,000 square feet

Destination B70,000 square feet

4 miles 10 miles

8 miles

Census tracksCensus blocks

Square feet of office spaceis a proxy for employmentor the mass (attraction) aspect in the model

398

10000,80

8000,70

4000,20

4000,20

000,1

222

2

XTripsA

254

10000,80

8000,70

4000,20

10000,80

000,1

348

10000,80

8000,70

4000,20

8000,70

000,1

222

2

222

2

XTripsC

XTripsB