Transport Demand Management and Travel Demand Elasticity: What We Know, What We Don’t Know, and Why Context Matters

Fri, 11 Dec 2026 00:00:00 +0000

American Geophysical Union Annual Meeting (AGU 2026), San Francisco, CA, USA, December 7-11, 2026.

Mobility is a basic need, and road infrastructure creates substantial social value by enabling access to employment, education, and services. Yet when demand exceeds capacity, congestion generates economic, environmental, public-health, and quality-of-life externalities. As supply expansion is increasingly constrained by budgets, space, and induced demand, transport demand management (TDM) is an important complement to infrastructure and vehicle-focused solutions. Market-based TDM instruments (prices, subsidies, tradable rights, quotas, reservation mechanisms) influence travel choices (departure time, occupancy, mode, ownership, frequency) by targeting whether, when, where, how, with whom, and how often roads are used. Despite proven effectiveness, these instruments remain among the most controversial policy measures due to distributive equity concerns, and can only produce their intended effect when travellers have realistic alternatives and sufficient flexibility to respond. Travel demand elasticity therefore governs TDM success, yet surprisingly little is known (both quantitatively and qualitatively) about how elasticity relates to the effectiveness and acceptance of economic TDM instruments, or how this should inform policy design. This study synthesizes the global evidence on TDM measures and travel demand elasticity through a systematic literature review, and develops a framework linking them with a quantitative meta-analysis, addressing: (1) how demand elasticity is measured across TDM instruments; (2) which behavioural margins (timing, route, mode, occupancy, frequency, ownership) drive observed policy responses; (3) how instruments should be designed when travellers differ substantially in their ability to respond; and (4) how elasticity affects implementation success and instrument choice.

Ines Azevedo | Kevin Riehl

Transport Demand Management and Travel Demand Elasticity: What We Know, What We Don’t Know, and Why Context Matters