Task: convert scenario description to json
Json Rules: "lanes" is the lane number of the road,"init" is an array that includes the objects involved in the scenario, "objectName" is the name of objects, "types" indicates the type of objects, including ["car","tricycle","bike","motorcycle","pedestrian","truck","emergency","animal","ice-cream cone","road stake","isolation fence","warning triangle","deceleration zone","wooden box","stones"], "initSpeed" indicates the objects' initial speed, "initPosition" is the objects' initial position: "laneId" is the id of the lane , "s" is the distance from the start of the road , "offset" is the objects' offset from the center of the lane 
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 la