Using GTFS-data to calculate the roadwork caused delays on public transport network

The reliability of public transport is a significant reason whether people choose it over other transport modes. Roadworks, i.e., mandatory road maintenance, can cause delays on vehicle journeys in parts of the network, thus generating missed transport connections. To sustain the reliability of the public transport system, it is important to understand effects these delays cause. This study explains a method that allows to model delay effects to the network using GTFS-data. The developed method allows a simple workflow to calculate how different delays on different locations affect the reachability of the areas. The method is tested in two case areas in Finland. Based on the case areas in this study, the results indicate that a 3-minute delay occurring for the departures from city centre only seldomly appears as a total travel time delay longer than the calculated delay. However, for some parts of the city that rely on transfer connections, even a 2-minute delay will result in missed connections, and thus, longer travel times.