Let's assume a driver's salary of 18 €/h. A rule of thumb I've heard is that vacation, sick days, social security etc. etc. approximately double that cost to th

Let's assume a driver's salary of 18 €/h. A rule of thumb I've heard is that vacation, sick days, social security etc. etc. approximately double that cost to the company, so 36 €/h. 20 kph average speed is already a somewhat generous value for a regular non-BRT city bus line, but let's use it for simplicity's sake, which gives 1,80 €/km driver's costs. Another rough value of thumb for city buses is that they use roughly about 30 l/100 km, which adds about 0,50 €/km, so 2,30 €/km for driver + fuel. A regular city bus holds about 100 passengers, and an average utilisation figure as averaged across the whole day and all routes might be somewhere around 20 %. So an average of 20 passengers per bus at all times, which means 11.5 cents per kilometre for driver and fuel. Now add-in capital cost for the bus itself, maintenance and other ancillary stuff and unfortunately 25 cents per kilometre isn't all that much all of a sudden. (If you can read some German, somebody did a more complete modelling of costs at https://prof.bht-berlin.de/fileadmin/prof/jschlaich/200811_Fr_JS_Kostenmodelle_NAHVERKEHR.pdf https://prof.bht-berlin.de/fileadmin/prof/jschlaich/200811_F..., and with some assumed fictitious but presumably plausible values ended up at 3,26 €/vehicle-km for a city bus operation in 2008 – and both (driver) pay and fuel have increased above inflation since then.)