# **1. Introduction**

Household surveys remain underutilized to understand transport choices such as expenditure level and composition, the economic impacts of traffic accidents, and the impacts of environmental policies such as vehicle restrictions or fuel taxes. While better transport infrastructure and services improve mobility and economic opportunities, transport is also a main source of CO2 emissions and is responsible for multiple injuries and death with dramatic impacts for households.

Household surveys can help us to understand better how to improve mobility for households while reducing the negative environmental and safety externalities. First, household surveys provide insights on transport affordability. Transportation affordability has received limited attention compared to housing affordability while high transport costs reduce the mobility of low-income households and limit their access to jobs, education, and health services. Household surveys provide disaggregated data on expenditures on regular costs such as fuel and insurance and on durable goods like vehicles ownership. Second, they document transport choices made by households to go to work, reach health or school facilities, and reach markets to buy or sell products. Third, they document the extent to which transport is a constraint for agricultural and non-farm production. Limited mobility reduces agricultural productivity and access to markets and can deter individuals from creating non-farm activities, slowing down the structural transformation of the economies. Finally, they can provide information on the economic impacts of traffic accidents when happening to a household member. Household surveys may include questions on the incidence of traffic death, injuries, and resulting disabilities experienced by the households, which are otherwise difficult to obtain. The lack of harmonization of transportrelated questions and the small number of questions has limited their use in providing stylized facts to inform works on transport mobility for the poorest, infrastructure investment beneficiaries, and environmental and road safety policies.

This paper reviews a set of household surveys, focusing on World Bank Living Standards Measurement Study (LSMS) surveys, to show their potential in providing insights on multiple transport-related questions. It then discusses the limits of such surveys and suggest a standard set of guidelines to design and harmonize transport related questions to improve future household surveys. The paper first reviews all World Bank LSMS surveys conducted since 2010 to list and categorize all transport-related questions. LSMS surveys include transport-related questions in multiple modules, which makes it difficult to have a comprehensive view of all transport-related questions for the whole survey collection. In addition, there is no consistency in the inclusion of transport-related questions in LSMS surveys across countries and over time. A main contribution of the paper is to list all transport-related questions in LSMS surveys for further work and categorize them. The paper also reviews non-LSMS surveys for comparison. The paper then shows how recent efforts to harmonize survey questions on consumption patterns and ownership of durable goods can bring interesting insights on expenditures across as well as within countries. Patterns differ significantly across countries based on their level of development, and 2