until discontinued in 2012, and these two facilities/measures, among others, have contributed to TriMet's having become one of the nation's most successful and most-studied public transportation systems. Prior to its closure for rebuilding in 2007, the Portland Mall's design permitted private vehicle traffic to use the left lane, but only in short, two-block segments. In every third block, the lefthand (auto) lane disappeared for one block, and the otherwise three-lane-wide street became two lanes wide and restricted to buses only. In this way, two-thirds of the specific blocks along 5th Avenue and 6th Avenue remained open to cars, but use of those streets for through travel by cars was prohibited. Design and amenities The 1970s rebuilding of 5th and 6th avenues as transit-priority streets included several changes designed to create an environment that was more attractive and inviting to transit users and other pedestrians. Sidewalks were widened and repaved in brick, many additional trees were planted, new works of public art were commissioned and installed, and amenities such as benches and flower planters were added. At each bus stop, a large new passenger shelter was installed. In addition to a pay telephone, every shelter was equipped with a closed-circuit television monitor giving riders information as to the next three departures on each bus route serving that particular stop. This particular feature of the Portland Transit Mall was said to be a "first" for urban transit at the time (1977), having previously been used only in intercity transportation terminals, mainly airports. The information system came into use in January 1978. The monitors were originally black-and-white, but were replaced by color ones in 1988. Most bus routes serving downtown Portland followed the transit mall, but a few remained on so-called "cross-mall" routings, along east-west streets, originally Morrison and Yamhill streets but shifted to Washington and Salmon streets with the start of MAX construction in the early 1980s. With regard to operations, the mall was designed with two bus stops in each block, or about one stop every . However, a bus operating on any given route only stopped at every fourth stop, i.e., every two blocks. TriMet adopted symbols and colors for each grouping of stops, so that bus riders could easily determine which particular stop locations were served by their routes. The colors/symbols, which were marked by large signs at each stop and also shown on public schedules and maps, were