(Oct 26) Transportation Planning: Induced Demand, Modal Split, and Policy Responses

Vocabulary practice flashcards covering key transportation engineering and planning concepts from the lecture, including induced travel, framing methods, carrots and sticks, international mode split variations, and vehicle technology impacts.

Congestion Framing

• Goal: reduce traffic delay

• Indicator: peak-hour speed or level of service (LOS)

• Target: LOS D or better at peak by 2035

• points towards widening, which induced demand undoes

• A transportation planning approach focused on reducing traffic delay using metrics like peak-hour speed or Level of Service (LOS), which typically prompts road widening

  • *we know that road widening / expansion does not actually end up reducing traffic delay and often making it worse

Accessibility Framing

• Goal: access to jobs and services without a car

• Indicator: jobs reachable in 45 min by transit, walking or cycling

• Target: X% of residents reach Y jobs in 45 min by 2035

• Points towards transit, land use and active travel

• A transportation planning approach prioritizing car-free access to destinations, measured by jobs reachable within 45 minutes by transit, walking, or cycling

  • *this is more likely to reduce traffic even though that is not its goal

Goals

• Broad, specific qualitative statements defining planning objectives

  • big picture

  • Utopian idea of how we picture the future / what we want it to be like

Indicators

• Quantitative measures used to assess progress toward or away from a stated goal

  • measure

  • what should we measure to know if we’ve reached our goal

Targets

• Specific desired endpoints established using indicators

  • always has a year

    • ex) “by 2030…”

Induced Demand (Induced Travel)

• The principle that expanding roadway capacity lowers the travel-time of driving, attracting new vehicular traffic, until congestion returns to previous levels due to all the new drivers

  • new road capacity attracts more driving

  • congestion eases at first, then returns

• supply and demand: faster driving = cheaper driving

  • traffic is not a fixed amount, it responds to changed because it is human (we cause traffic, we respond to changes)

Duranton & Turner (2009) Study

An empirical analysis of U.S. metropolitan areas from $1980\text{--}2000$ demonstrating that a $1\%$ increase in lane-miles results in an approximate $1\%$ increase in vehicle-miles travelled (VMT).

Level of Service (LOS)

A conventional traffic engineering indicator that grades roadway congestion and motor vehicle delay on a scale from $A$ to $F$.

Institutional resistance to accepting that road widening does NOT relieve congestion long term

• Agency divisions:

  • Urban planners: convinced that widening doesn’t work

  • Engineers: not convinced (less likely to be taught this)

• Industry and lobbying favor widening

• Rural states still link freeway access to growth (economic etc.)

• there is always a job or growth argument for widening roads

  • construction jobs or more travelers passing through bringing in business

Carrots (Transportation Policy)

• Incentive-based improvements designed to encourage sustainable travel choices, such as reliable transit, bike networks, and walkable neighborhoods

• Frequent, reliable transit

• connected bike networks

• walkable, mixed-use neighborhoods

• fare discounts and incentives

• popular, but freed space refills

Sticks (Transportation Policy)

• Disincentives, such as congestion pricing and parking limits, designed to discourage driving and manage travel demand

• congestion and road pricing

• parking pricing and supply reallocating road space

• lower speeds, car-free zones

• effective, but seen as unfair without options

together the options make the charge fair (the charge protects the gains = the sticks protect the carrots)

Why combine carrots and sticks?

Congestion Pricing

A fee charged for driving in congested zones during peak hours to discourage driving and fund public transit

• most effective tool (least popular)

High-Occupancy Vehicle (HOV) and Toll (HOT) Lanes

• Highway lanes reserved for carpools and toll-paying drivers

  • while they improve flow for paying drivers, general lanes refill via induced demand, leading to net increases in traffic and emissions

  • net result: more traffic and emissions

Goal should be environmentally responsible accessibility (not congestion relief)

What should to Goal be in car-dependent places?

Walking is more dangerous in the US

• US pedestrian deaths per capita rose 25% in 2010-2020; canada’s fell 7%

• larger vehicles in the US (more trucks) compared to in Europe

• Cheap fuel in the US compared to in Europe

• Wide, fast roads designed for vehicle flow

  • roads designed for mobility not accessibility

• weak enforcement of speeding, drink and distracted driving

policies for more and safer walking

• connected sidewalks and safe crossings

• streets and intersections designed for pedestrians

• mixed-use zoning and short trips

• lower speed limits

• less parking, prices higher

• pedestrian priority in traffic law

• traffic education for drivers and children

• taxes on large vehicles

• stricter enforcement of drunk and distracted driving laws

Mumford

• this author:

  • put the pedestrian at the centre

  • scrap single-use zoning

  • smaller town cars

  • more roads bring more traffic

  • learn from European cities

Buehler & Pucher

• This author:

  • walking networks, pedestrian-first streets

  • mixed-use zoning (building diversity)

  • taxes on large vehicles

  • less parking, higher prices

  • five decades of European evidence

  • adds: safety and enforcement

  • most modern

Strict Liability

• A legal statute under Dutch law making drivers liable for at least $50\%$ of damages in collisions with pedestrians or cyclists regardless of fault, and $100\%$ liable if the injured person is under $14$ years old.

• discourages drivers and holds them more accountable because they can do more harm

Pucher's Public Policy Hypothesis

The proposition that differences in travel mode choice stem primarily from public policy rather than cultural preferences

Pucher’s (in Automobile Dependency / Modal Split)

• North American purchase and use cars more than Europeans, not because they have a preference for driving over other modes of transpo, but because the infrastructure and policies give them no choice

  • its either drive a car or be immobile

Mode Split

The proportion of total passenger trips made using each mode of transportation.

“Green” Cars

• cars such as AVs and electric cars

• sustainable?

  • sustainability is a context, not a object

  • it is not the machine that is sustainable it is peoples practices

    • if people still use these vehicles as much as others or even more then it is not sustainable as it is still using as much or even more energy

    • also the fact that these vehicles are “more efficient” only allows people to drive more (does not decrease pollution, if anything increases it)

Non-Exhaust Particulate Matter ($\text{PM}_{2.5}$)

• Fine particulate air pollution caused by tire friction and brake wear that is not eliminated by transitioning to electric vehicles and is often exacerbated by heavier vehicle curb weights

congestion won’t be reduced by making mobility easier on its own, need other land use and behavioral changes

Remember: congestion won’t be reduced by making mobility easier on its own, need other land use and behavioral changes