Task: convert scenario description to json
Example:
Scenario: 
1. One-way two-lane straight road
2. There are three objects: Ego(car) is in the second lane , carA(car) is in the second lane, carB(car) is in the second lane
3. Ego's initial speed is 50km/h, carA's initial speed is 40km/h, carB's initial speed is 30km/h
4. Ego is 100m from the start, carA is 40m in front of Ego, carB is 40m in front of carA

Json:
{"road":{"lanes":"2"},"init":[{"objectName":"Ego","type":"car","initSpeed":"50","initPosition":{"laneId":"2","s":"100","offset":"0"}},{"objectName":"carA","type":"car","initSpeed":"40","initPosition":{"laneId":"2","s":"140","offset":"0"}},{"objectName":"carB","type":"car","initSpeed":"30","initPosition":{"laneId":"2","s":"180","offset":"0"}}]}

convert the following scenario to json:
1. One-way three-lane straight road
2. There are three objects: Ego(car) is in the second lane , carA(car) is in the second lane, cone(ice-cream cone) is in the second lane
3. Ego's initial speed is 30km/h, carA's initial speed is 60km/h
4. Ego is 50m from the start, carA is 40m in front of Ego, cone is 30m in front of carA