TraCI/Control-related commands

Control-related commands#

Command 0x00: Get Version#

no parameters

Response 0x00: Version#

integer string
API Version Identifier

The server responds to a Get Version command by sending two items:

  • an API Version of 10 identifies the current state of the TraCI API (sumo 0.24.0 or later).
    • It is guaranteed to increase as soon as
      • the TraCI message format changes
      • the TraCI command format changes
      • any TraCI command has a different meaning (e.g., "0xff: stop" changes from "stop immediately" to "slow down, then stop if possible")
      • any TraCI parameter has a different meaning (e.g., a "time" parameter changes from seconds to milliseconds)
      • addition of a new command
      • removal of a command
      • addition of optional parameters
      • addition of optional parameter types
      • addition of optional result types
    • The API version is only incremented for releases and not inbetween
  • an identifier string identifies the software version running on the TraCI server in human-readable form
    • no guarantee is made regarding the content of this string
    • as an example, for SUMO 0.12.0, this string is "SUMO 0.12.0"


The client can find out if a particular command is supported by the current TraCI server (i.e., SUMO) by looking at the status response of the command. It may report "not implemented."

Command 0x02: Simulation Step#

TargetTime [s]

Forces SUMO to perform simulation. If TargetTime is 0 (zero), SUMO performs exactly one time step. Otherwise SUMO performs the simulation until the given time step is reached. If the given time step is smaller than or equal to the current simulation step then SUMO does nothing. For multi client scenarios currently only TargetTime 0 is supported.

The response of this command is a list of subscription responses to TraCI/Object Variable Subscriptions and/or TraCI/Object Context Subscriptions referring to the last step executed:

Number of following subscription responses <RESPONSE#1> ... <RESPONSE#n>

Please note, that both subscription types differ in their return values, so the parser should regard the id of the returned command.

Command 0x7F: Close#

Tells TraCI to close the connection to any client, stop simulation and shut down sumo.

Command 0x01: Load#

option list

Tells TraCI to reload the simulation with the given options.


Loading does not work when using multiple clients, currently.

Command 0x03: SetOrder#

number of the client

Tells TraCI to give the current client the given position in the execution order. It is mandatory to send this as the first command after connecting to the TraCI server when using multiple clients. Each client must be assigned a unique integer but there are not further restrictions on numbering.