There are eight circles, or roundabouts, that span and connect west Amman. Successive waves of immigrants to the city has led to the rapid construction of new neighborhoods, but Amman's capacity for new or widened roads remains limited despite the influx. This has resulted in increasing traffic jams, particularly during summer when there are large numbers of tourists and Jordanian expatriates visiting. The municipality began construction on a bus rapid transit (BRT) system as a solution in 2015. In 2015, a ring road encompassing the city was constructed, which aims to connect the northern and southern parts of the city in order for traffic to be diverted outside Amman and to improve the environmental conditions in the city.