Universal Accessibility in Public Transport in Context of Bangladesh

Tanmoy Biswas1, Avishek Kumar Dey2, Pankaj Kumar Sutradhar2, Tapos Paul2, Debabrata Karmakar3

1Department of Civil Engineering, 2Department of Mechanical Engineering, 3Department of Chemical Engineering,

Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

Abstract

Universal access is the goal of enabling all citizens to reach every destination served by their Public Street and pathway system. Universal access is not limited to access by persons using automobiles, travel by bicycle, walking, or wheelchair to every destination is accommodated in order to achieve transportation equity, maximize independence, and improve community livability. Wherever possible, facilities are designed to allow safe travel by young, old, and disabled persons who may have diminished perceptual or ambulatory abilities. By using design to maximize the percentage of the population who can travel independently, it becomes much more affordable for society to provide Para transit services to the remainder with special needs. But in Bangladesh there is we never think about the accessibility of wheelchair dependent person in public transport. In this Project we Design existing BRTC (Bus WG6110N) bus to make it accessible for wheelchair dependent person.

1. Introduction

In the western country they use low deck bus because roads are very smooth there and they thought about the universal accessibility of their every citizen. They are trying to make a society where there is no deference between physically disable and able man or woman. But in our country we use high deck bus which is suitable for our roads and highways. So a large part of population whose are physically disable specially wheel chair depended person cannot access the public transport. Because high deck buses have stairs. By using stair passengers have to lift into the buses. But stair is always an obstacle for a wheel chair person.so they cannot access any of our public transport. Bangladesh roads and transport corporation (BRTC) is the stage-owned transport corporation of Bangladesh. They import Chinese high deck buses which have stairs and its not universal accessible. Here in this paper we are going to show/introduce an idea following which this bus can be converted to a universal accessible bus.

2. Obstacles

First obstacle is inconsistency of height of our existing footpath of Bangladesh. And main obstacle for wheelchair person is to get on board of the bus using stairs. In cities in Bangladesh we use high-deck bus instead of low-deck bus. And we use stair to get on board of the bus. Using stair is impossible for wheelchair person. Second obstacle is placement of wheelchair in bus. In our existing bus there is no vacant space for wheelchair placement.3. Methodology

To overcome the First problem we redesign middle door stair of our existing BRTC bus. In our design stair is as usual in all dimension [1]. So general people can use it easily (they cant even detect any change) to get into and get out of the bus. When a person with wheelchair comes to bus gate, bus stair will be converted to a vacant space. He gets on lower deck of stair from footpath. Then lower deck will lift the person to bus floor height. Then wheelchair person can easily get on board of the bus.

Fig01: side view of the stair in normal position

Fig 02: side view of the stair on sliding

Fig 03: Side view of the stair after sliding

Fig 04: After lifting the 1st step to the level of bus floor

4. Modification

We are going to change/modify 3 things1. Platform Modification2. Door Modification3. Seat Plan Design

4.1 Platform/Footpath modification

The standard size of footpath is 35 cm. But in Bangladesh it is not maintained strictly [2]. In our design all we need do is just make sure all footpath/platform are in standard size. If it is not possible we need standardized the height footpath at the bus stoppage. For make footpath accessible for wheelchair dependent person the end point of the footpath have to be sloppy. And here we follow 1:12 ratio for the footpath ramp, which is the standard ramp ratio for wheelchair [3].

Fig04: Side view of footpath

4.2 Door Modification:

In the imported Chinese BRTC buses door is automated by hydraulic system. Hydraulic mechanism is kept in middle stair. But as our middle stair is not fixed we have replaced the hydraulic mechanism inside of bus under a passenger chair. And this kind of automatic hydraulic door mechanism already exists in the old model of BRTC Buses. These mechanism is shown below:Fig 05: Door Opening & Closing Mechanism

4.3 Stair modification:

High deck buses usually have 3 stairs. In our modification our stairs are as usual in dimensions [4]. When the normal passengers will come they found the stair as usual but when a wheel chair [5] [6] dependent person will come following mechanism will be performed in the stair.

4.3.1 Sliding mechanism:

We are proposing to slide lower step forward and middle step backward simultaneously. For this we use Rack and Pinion method [7]. Two links with pinion/rack are attached with lower step and middle step. Motion of lower step and middle step are in opposite direction, so we use gear to do this. As displacement of lower step and middle step are different so we use spur gear [8]. Both stair and deck will be on roller in order to slide freely. There will be a locking system to make it easy to board on bus for general people in usual case. Power will be supplied from buss battery to rotate the motor to rotate the spur gear for sliding mechanism.

Fig 06: Lower Step Details

Fig 07: Mechanism of Sliding

Fig 08: Plan view of Stair mechanism.

4.3.2 Lifting (Scissor Mechanism):

We use two deck of steel as lower step of stair. In our design lower deck can move horizontally and make enough space for wheelchair. We use six rod to lift the upper deck. Six ends are in fixed support whereas rest six ends are in roller support. In mid-point of rods are pinned. So when force is exerted on roller support it will lift the upper deck [9].

Fig 09: Lifting Mechanism (Scissors Mechanism)

5. Seat plan design:

We two different design of seat plan to accommodate wheelchair.1. Design A: Accommodation for 1 wheelchair dependent person.2. Design B: Accommodation for 2 wheelchair dependent person.

5.1 Design A:

In this design, we dont omit any seat at all. We just modify orientation of seat plan. We just flip the orientation of a 3-seat-rowjust opposite the door. As dont omit any seat, so there can be seated as many people as in normal bus. But we will change 2 face to face 3-seat-chair row by folding chair. In usual time 6 people will sit face to face. When a wheelchair dependent person come those person give their seat for wheelchair dependent person. Now seat is folded up and thats make a vacant space. Now wheelchair dependent person just easily accommodate to this vacant space and lock up himself for safety. Details are shown in figure. So in Design-A, we accommodate 1 wheelchair person and dont omit any seat.

Fig10: Design-A unfolded

Fig11: Design-A folded

5.2 Design B:

In this design, we will accommodate 2 wheelchair dependent person in our bus. For doing this we omit a 3-seat-row and flip the orientation of its immediate front 3-seat-row. As we omit 3-seat-row, so there can seat 3 person less than normal bus. In this design we replace immediate front and behind 3-seat-row by foldable chair. So when a wheelchair dependent person comes, he/she will found enough vacant space between two face to face 3-seat-row. When two wheelchair dependent person come at a same time, first person gets his space by folding front seat and other person gets his space by folding behind seat. So in this design 2 wheelchair dependent person will seat side by side and in perpendicular direction to the bus. So in Design-B, we accommodate 2 wheelchair person at same time and omit a 3-seat-row.

Fig12: Design-B unfolded

Fig12: Design-B unfolded (Accommodate one Wheelchair)

Fig14: Design-B unfolded (Accommodate two Wheelchairs)

Fig15: Seat Folding Mechanism

6. Hydraulic mechanism & pump specification:

We use hydraulic mechanism here for lifting the scissor linkage. We assume including the safety factor total load is 250kg. If the actuator shaft diameter is 100mm. the pump have to create 78065.50pa pressure in the hydraulic fluid [10]. We calculate the pump head 28.52 ft.

Fig16: Hydraulic pump Specification

7. Rack-pinion, Spur gear & motor specification:

There is rack pinion for sliding the middle stair inside and lower stair outside simultaneously. Here pinion is a spur gear which is mounted in the shaft of a electric motor. Motor is powered by the bus Battery.

Fig17: Spur Gear, Motor Specification.

8. Accessories:

We suggest special signal light and sign convention would be introduce in the roads side. It will help the driver to know whether there is any wheelchair dependent person or not. We if any kind of belt can be provide, it will provide support the wheelchair lifting. We would place the wheel chair in bus in transverse direction.so it is little chance to slide the wheel chair when bus moves. But for safety we use locking system to lock the wheel chair.

9. Cost and replacement:

The idea is cost efficient. Approximate total cost for the stair modification is approximately eighteen twenty thousand BDT. Every equipment we used here can be easily replaceable.The roller, bearing and universal joint used here are in standard size so these can be found easily in the local market

10. Advantages:

a. Stair is as usual with dimensionb. Need less time to convert from one to anotherc. Need very less energyd. Cost efficient e. Sustainablef. Only few seat is omitted. 3 seat for 2 wheelchair person and no seat for 1 wheelchair personReferences:[1]Inter University Design Contest, a joint initiative by ESAB & B-SCAN. (http://www.facebook.com/esab.bd/posts/634901326535437)

[2]Evaluation of roadside walkway environment in Dhaka city (Proceedings of the Eastern Asia Society for Transportation Studies, Vol. 5, pp. 1751 - 1766, 2005)

[3]American Disabilities Act (ADA) ramp ratio for wheel chair.[4] http://www.ecplaza.net/trade-leads-seller/bus-wg6110n--5644632.htm[5] http://suntran.com/pop_access_measurements.htm[6] http://www.access-board.gov/vguidedraft2.htm

[7] http://www.slideshare.net/aliwaqas/rack-and-pinion-gear-design-project[8] Shigleys Mechanical Engineering Design, 9e(SI unit) by Richard G. Budynas and J. Keith Nisbett, Tata McGraw Hill Education Private limited.

[9] Scissor Mechanism (http://envisioningmoore.com/Engineering/031011%20Inner%20Scissor/Scissor%20Lateral%20Beam%20Report.pdf)

[10] Mechanics of fluids, 4e, Irving H. Shames, McGraw Hill international Edition.