# Social Cost Guarantees in Smart Route Guidance

## TL;DR

This paper introduces moneyless, manipulation-resistant mechanisms for assigning routes in urban traffic networks, ensuring near-optimal social costs despite strategic driver behavior, with both theoretical guarantees and practical validation.

## Contribution

It presents novel moneyless mechanisms with provable approximation guarantees that resist strategic manipulation in traffic routing, combining theoretical analysis with empirical testing.

## Key findings

- Mechanisms achieve near-optimal social costs under strategic behavior.
- Empirical results demonstrate practical effectiveness of the proposed mechanisms.
- Mechanisms are resilient to manipulation without requiring monetary incentives.

## Abstract

We model and study the problem of assigning traffic in an urban road network infrastructure. In our model, each driver submits their intended destination and is assigned a route to follow that minimizes the social cost (i.e., travel distance of all the drivers). We assume drivers are strategic and try to manipulate the system (i.e., misreport their intended destination and/or deviate from the assigned route) if they can reduce their travel distance by doing so. Such strategic behavior is highly undesirable as it can lead to an overall suboptimal traffic assignment and cause congestion. To alleviate this problem, we develop moneyless mechanisms that are resilient to manipulation by the agents and offer provable approximation guarantees on the social cost obtained by the solution. We then empirically test the mechanisms studied in the paper, showing that they can be effectively used in practice in order to compute manipulation resistant traffic allocations.