Design Concept
System Design
To determine the optimal concept to reduce traffic density and local air pollution, the team compared three concepts with the below scoring matrix. The three ideas were: a tunnel system of roads, a carpool lane, and an app connecting users who wish to carpool together.
The matrix shows that the tunnel concept was poor due to safety concerns and startup and maintenance costs. However, the carpool lane and carpool app scored similarly, but the carpool app scored slightly higher due to lower startup cost and time.
| Existing local transportation | Tunnels | Carpool App | Carpool Lane | ||||||
| Needs | Weight | Rating | Weighted Score | Rating | Weighted Score | Rating | Weighted Score | Rating | Weighted Score |
| Time to Deploy | 3 | 2 | 6 | 1 | 3 | 4 | 12 | 3 | 9 |
| Upfront cost | 4 | 3 | 12 | 1 | 4 | 5 | 20 | 4 | 16 |
| Difficulty of Maintenance | 3 | 2 | 6 | 1 | 3 | 4 | 12 | 3 | 9 |
| Reduction in traffic density | 5 | 1 | 5 | 4 | 20 | 3 | 15 | 3 | 15 |
| Simple to use | 3 | 4 | 12 | 3 | 9 | 3 | 9 | 4 | 12 |
| Safety | 5 | 3 | 15 | 2 | 10 | 4 | 20 | 5 | 25 |
| Scalability | 2 | 3 | 6 | 2 | 4 | 5 | 10 | 4 | 8 |
| Accessibility (Can be used by anyone) | 2 | 4 | 8 | 3 | 6 | 4 | 8 | 5 | 10 |
| Total Score | 70 | 59 | 106 | 104 | |||||
| Rank | 3 | 4 | 1 | 2 |
The system Watts Transportation will thus implement will consist of a social network designed to connect users who wish to carpool together. This will be primarily implemented with a mobile app that will connect users similar to other social networks such as Facebook or Tinder. This system will enable people who wish to cut their fuel cost to do so by carpooling.
Concept Sketch of User Interface
Vehicle Design
To model this system, Watts Transportation will design the ideal vehicle used for carpooling under this system. This vehicle is ideally one that seats more than five people, but is fuel efficient, has a short turn radius, and short stopping distance. These needs will ensure that a driver operating in this system can drive several people quickly and safely. This will allow the company to model how the vehicle would interact with the overall Columbus transportation system.
To ensure quality of both the actual vehicles and the prototype, the team drafted the following set of design requirements for testing. This will allow the group to gauge the viability of such a project on a large scale.
| Actual Vehicle | Prototype | ||
| Requirement Description | Accepted Range of Values | Preferred Value | Ideal Value |
| Load | At least 5 passengers | At least 7 Passengers | 2 Cabooses |
| Mass | <4,000 lb | < 3,000 lb | <150g |
| Wheel-Weight Distribution | 40/60 – 60/40 | 45/55 – 55/45 | 45/55 – 55/45 |
| Fuel efficiency | 28 city mpg, 35 highway mpg if gas, 200 miles if electric | 30 city mpg, 40 mpg highway if gas, 250 miles if electric | 100,000 marks per battery |
| Speed | Can reach 70 miles per hour | Can reach 90 miles per hour | 7.88 marks/sec |
| Stopping Precision | <10 feet per 10 miles per hour | <8 feet per 10 miles per hour | <0.45 marks per mark/sec |
| Detection Range | 0 to 450 feet | 0 to 500 feet | N/A |
| In-car Wi-Fi | 25 Mb/s | 50 Mb/s | N/A |
| Acceleration | 0-60 mph in <11 sec | 0-60 mph in <6 sec | 0-4.77 marks/sec in <6 sec |
As an initial design, the team built the following prototype vehicle:
Initial Prototype Vehicle
In addition, passenger and pedestrian safety is the highest priority of Watts Transportation. As a result, the stopping precision of the vehicle was taken into consideration from the beginning, with the team designing a piece of code to stop the vehicle from a given speed.
Prototype Vehicle Braking Code
This code reverses the motors and spins them for an amount of time relative to the time the vehicle spent accelerating. This was designed to generate a force opposite to the direction of the velocity of the vehicle to quickly stop it.