Crazy Taxi and Jambo Safari are very close to each other IO-wise. The only difference is where the two games place their shifter up/down digital inputs on the 2x30 JST header. It is possible to run two bridge wires between the two games' inputs and have your standard sit-down cabinet capable of playing both games.
Given the above diagram of the Sega JVS IO Type 1, the 2x30 pin JST connector is where all of the controls are connected. Assuming pin 1 is the top left pin in the connector, and we count right then down (so the top row is pins 1-30, bottom row is pins 31-60), the following pins must be connected together:
- Pin 18 to pin 49.
- Pin 19 to pin 48.
An example of a Crazy Taxi that has been wired to also run Jambo Safari is pictured below. Note the two orange jumper wires running from the two gray shifter input wires, which are connected in a criss-cross pattern: