**1. Introduction**

Within major cities, the transportation network serves as an essential component in its functionality allowing for the movement of goods, services, and the general population, with an estimated 81.7 thousand vehicles per mile of motorway, and 12.2 thousand miles of rural "A" roads per day within the UK [1].

The implications of flooding within the road network can be severe both in terms of risks to human lives both directly as a result of drowning and indirectly due to impacts on the ability of first responders to respond to incidents [2–4] as well as to a region's economy. Flooding in Barcelona 2011 disrupted the transport network both directly as a result of flooded road sections and indirectly as a result of traffic light failures [5]; the traffic disruption alone caused by the Summer Floods of 2007 in the UK cost the UK economy in the range of £22–£174 million (depending on assumptions) [6].

From a climate change perspective, the Department for Transport have stated that the Strategic Road Network (the main roads that connect the country) has been identified as being particularly vulnerable to weather-related flooding [7], with Highways England highlighting that the current drainage systems in place may not be sufficient to deal with the increased rainfalls associated with climate change predictions [8]. The UK Climate Impact Projections Report 2009 (UKCP09) predicts the precipitation across the UK will increase up to 70% in certain locations by the 2080's [9], which could result in more frequent and greater levels of disruption to traffic movements.

Previous works have investigated both the risks and impacts of flooding poses to the transport sector such as the combined interactions of flood depths and flow velocities on vehicular stability [10,11], the relationship between vehicular speed and standing water depths on road surfaces [2,12–14] and the significance of which roads within a network are flooded [15].

This paper investigates the impacts on traffic of pluvial flood events in two European cities (Barcelona and Bristol) via linking flood model outputs with traffic models and examine how the magnitude of these impacts could change in the future with respect to climate change model predictions.
