- By Zaw Min (GNLM)
Bus and truck
In the early days of manufacturing bus and trucks, the chassis design was shared between trucks and buses as both were heavy carriers of either loads or passengers. A chassis combines a frame; engine and a radiator; gearbox and transmission; wheels, axles and suspension that was often built as a complete unit enabling it to be driven to the body builder where a body was built to carry load as a truck or passengers as a bus.
In the early days when a common chassis design was used by a bus and a truck, the bus passengers had to climb up several steps to board a bus. This can be seen in the old model buses that still ply Yangon or on the highways.
But considering the significant difference between carrying loads (that just need a space) and passengers (that need space as well as comfort and convenience) specific bus chassis have been developed.
In the 1990s, bus manufacture underwent a major change toward low-floor design for improved accessibility of the passengers.
City Bus and Coach or Highway Bus
In the world today city buses ply a city along designated routes depending upon the city’s layout for urban population to commute easily. Meanwhile, coaches or highway buses linked one city from another for inter-city travellers. Up to late 20th century, the basic design and construction of city bus and highway bus were just about the same with the only difference being the layout and numbers of seats. It was also using a common chassis that was also used for trucks.
Seats on city bus were of simple design for normal short haul trips with seating arrangement allowing more areas for standing passengers to maximise mass transit of the commuters. Highway bus seats were of a better ergonomic design that was convenient for passengers to remain seated throughout a long haul trip and there were no standing areas except a centre walkway.
The main difference between a city bus and a coach or highway bus was seats for long or short haul and a requirement of an overhead or under floor storage of passenger baggage in the highway bus.
In addition for both city bus and highway bus going toward a low-floor design for improved accessibility of the passengers, early 21st century automotive engineers and designers also begin to notice the different natures of a short haul city bus and long haul highway bus not only in the seating/standing areas, seating convenience and storage capacity. Except for winding routes going up or down hills and mountains most highway bus travels on an almost straight line routes at a more or less a constant speed. It was estimated that highway bus went on a straight line almost 90 percent of its journey. City bus on the other hand was a reversal of the highway bus with the majority of its route involving twists and turns along the city roads with more stops and goes as well as changing of speeds due to heavy traffic.
There are also gyroscopic effects of rotating parts and centrifugal forces of a mass going around or making a turn that came into play for both city bus and highway bus. As long as the design and make of the city bus and highway bus were catered to how it was used, there’ll be continuous improvement in the comfort and safety of the bus/coach operators, users (passengers) as well as for the general public even if the public was simply sharing the roads the buses and coaches ply be it a city street or an expressway.
Main consideration of authorities and operators
Main consideration of authorities like Yangon Region Transport Authority, operators of City Bus lines/routes and city bus owners should be knowing the difference between a city bus and a coach or a highway bus and to use a proper city bus that was designed specifically for short haul in-city routes rather than use any bus of any design that were not made for public transport in a city.
Reference: Modern city buses and urban transportation by Science Writer Ko Ko Aung