Jakarta has the worst traffic congestion in the world according to a CASTROL study. The main causes of Jakarta's traffic jams are inadequate public transportation, with only 20% of citizens using it compared to 50% in Singapore and 90% in Hong Kong. The number of private vehicles is increasing by 12-13% annually while road expansion is only growing at 0.1% per year, leading to over 6000 new vehicles on roads daily. Other factors making traffic worse are narrow roads obstructed by street vendors and haphazard parking, as well as a large number of commuters entering Jakarta daily from surrounding areas.