I have used the design of the steering handle used in design 3. This is because the steering handle  of design three is curved. This provides the riders different types of grips, thus riders can choose the grip that they prefer the most according to its comfortableness. Hence, different to other designs, the riders will have a more comfortable grip of the steering handle, thus meets design specification 3.1 extensively. Therefore, the design of steering handle used in design 3 was chosen to be used in the final design. 

I have used the saddle design used in design 4 for numerous reasons. First, the saddle of design 4 is easiest the build, but is the most steady, thus it is the most efficient and effective design. This is because there is a single long saddle available for two people, but other saddle designs are two separated pieces, which takes more time and effort to build as it has more joints and more cuts are required. Second, the single long pieces saddle design provoke creativity where other designs limits the kids creativity while cooperating. Therefore, the design meets the design goal to allow kids to learn communication and cooperation while having fun. This is because the long piece design requires more communication and cooperation for the kids to use as they are seating on a single saddle, thus they will have to cooperate in order to sit not he saddle. Moreover, they will be closer together physically, inducing more communication. On the other hand, other dieting have two operate saddles, which doesn’t require as much as communication and cooperation from the kids. 

1.1 There must be at least one cartoon character or movie hero painted on the frame of the bike

1.2 All the parts of the bike must have the same color scheme with the character drawn on the frame of the bike

1.3 The bike must have at least three colors 

Function

2.1 The bike must be available for two people to ride at the same time

2.2 The wheels of the bike must be able to roll or spin when the rider push forwards agains the ground with force

2.3 The direction of ride can be controlled by rotating the steering handles towards the direction wanted 

2.4The steering …  and the fork must be able to rotate independently from and frame

Form

3.1 The shape of the steering handle must fit the ergonomics of human hands 

3.2 The shape and design of the saddles must fit the ergonomics of human

Safety

4.1 Users must be able to balanced on he bike when riding

4.2 All the vertex points of the bike must be rounded to prevent cuts and injuries while riding

4.3 Proper carpentry joints will be used for all the different parts of the bike in order for the bike to be steady and not break while being used

Size

5.1 The frame of the bike must be minimum 500mm x 300mm x 40mm and maximum 600mm x 450mm x 50mm

5.2 The width of the handle must be minimum 300mm x 30mm x 30mm and maximum 500mm x 40mm x 40mm

5.3 The height of the saddle must be 500mm 

5.4 The size of the whole bike must minimum 1000mm in length and 550mm in height, maximum 1200mm in length and 650mm in height 

5.5 The fork of the front circle must be at least 50mm thick 

5.6 The saddle must be minimum 100mm x 100mm and maximum 200mm x 200mm

5.7 The sponge cushion of the saddle must be at least 20mm in depth. 

Material

6.1 The fork must be made from iron such as steel

6.2 The saddle must have a sponge cushion on the surface 

6.3 The handle bar must be made from wood and have smooth rubber material rapped around