Incentive compatibility strategies to prevent cheating in incentive-based travel demand management

Cheating is widespread in societies and results in considerable societal costs. In Incentive-Based Travel Demand Management (IBTDM) programs, cheating is particularly likely because attractive financial rewards and limited monitoring may encourage commuters to misreport information, thereby weakening the effectiveness of demand-management incentives and challenging the fundamental rationale of IBTDM. Despite this risk, a systematic analysis of cheating motivations and countermeasures remains lacking. This study addresses this gap by examining cheating behavior arising from misreported target arrival times in departure-time–oriented IBTDM programs and by developing incentive-compatible (IC) mechanisms that induce truthful reporting. Building on the bottleneck model with heterogeneous commuters, we show that commuters sharing the same target arrival time behave identically. In equilibrium, commuters belonging to a minority group tend to misreport as members of the majority group. Based on the behavioral insights, we propose four IC strategies to elicit truthful reporting. When cheating occurs only above a reward threshold, a temptation mechanism that progressively expands the reward budget can effectively eliminate cheating under discrete and continuous arrival-time structures. When cheating persists at any reward level, in two-group arrival-time settings, penetration-rate control and adjustments to the reward allocation period can restore truthful reporting. In multi-group or continuous settings, a VCG-based mechanism provides the most robust incentive compatibility, although it does not reduce the total reward budget. These findings contribute to the design of more robust, efficient, and truthful incentive-based policies for travel demand management.