Figure 2
![Figure 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1471-2458-5-123/MediaObjects/12889_2005_Article_278_Fig2_HTML.jpg)
Composite traffic trips by vehicle type as a function of time. The fraction of composite trips (composite fraction) is 50% of the current 1.3 million personal car trips per day. Note that a trip with a transfer is calculated as two half-trips and may appear in two different vehicle types.