As cities become more crowded, cars are being set aside as the primary means of transportation. The automobile’s “footprint” is huge when considering the amount of square footage it requires just to be parked. The cost of owning and driving a car in a large Metro Region is outrageous. New construction of subways and fixed rail projects are not only prohibitively expensive but construction tears up neighborhoods for years. Bus transit is less intrusive, more flexible and cost-effective compared to these other forms of transportation. The “Articulated” bus has been around for many years but is becoming popular with transit companies as a way to carry more passengers. These vehicles will become very popular as way to move large numbers of passengers but they have limitations. I have driven buses including articulated type in the Metro Detroit area for five years and in this article I will talk about some of the opportunities and problems these flexible buses present.
Articulated buses stand out from regular buses because they have three axles, they are really a shorter bus with a trailer and the distinctive “accordion” bellows-like joint that allows the passengers to move freely from front to rear. Articulated buses are powered by a diesel-electric hybrid motor with a large battery. This power unit is behind the rear axle in the trailer unit. Regenerative braking helps to charge a large battery which then is used to accelerate the bus. These buses can carry many passengers while reducing both cars and shorter buses on the road.
Several things must be kept in mind when designing a system with articulated buses:
- Because the heavy weight of the motor and generator is located behind the axle in the trailer unit, this creates a whip-like action and the wheels of the trailer unit can easily slide with little warning to the driver. This sliding pushes the rear wheels of the front unit in the opposite direction making the vehicle hard to control. Drivers need extra training on a skid pad for these handling characteristics.
- Because of the extreme length of the vehicle there is a lot of conflict with traffic coming along side. This length also distorts the drivers depth perception when looking into the rearview mirrors much like railroad tracks do. The nature of the bending of the bus blinds the driver’s view even in small curve in the road; all she can see is the side of the bus in the mirror. Outside camera monitors for the driver are needed.
- Routes must be carefully designed so merging to the left or right is not required. Driver rest and dwell points must be able to accommodate this large vehicle.
- Dedicated bus lanes are ideal but where these HOV lanes are not practical every effort must be made to keep the right lane open by local city police.
- Value is negated because of the large number of passengers and the slow process of cash-fare inserted into a fare-box during boarding. Swipe, wave cards or smart phone optic readers must be used or fare will be paid before entering bus loading area.
- Articulated buses should be used as express, limited or park and ride duty.
- At stops where large numbers of passengers board and exit, concrete pads need to be installed level with the floor of the bus. Folks in wheelchairs or with mobility disabilities can easily board while speeding the loading and disembarking of all passengers
- These buses should be able to communicate with traffic control devices (stop lights) to avoid sitting at red lights.
- In Windsor, Canada, traffic laws require following and overtaking vehicles to yield to a bus with their turn signal on pulling out into traffic to yield to the bus. This simple law would help a great deal to keep all buses on schedule and save valuable fuel.
Many times systems, products and devices are put into service and the actual users are never consulted. If more attention were paid to users at the conceptual stage (really like making drawings on a paper napkin!) much time, effort and money could be saved. If users had a voice during the research, design, engineering and build stages, users such as drivers, mechanics and most importantly passengers would have a great of affection for the buses and transit system in general.