Sublane-Model

This page describes simulations with increased lateral resolution. This model is useful to simulate the following:

• multiple 2-wheeled vehicles driving in parallel on a single lane
• vehicles overtaking a bicycle on a single lane
• formation of virtual lanes in dense traffic (i.e. 3 vehicles driving in parallel on 2 lanes)
• virtual lane formation for emergency traffic
• lateral dynamics
  • lateral acceleration and speed
  • blocking of 2 lanes during overtaking
  • bicycles drive on the rightmost side of a lane
  • lateral encroachment by aggressive drivers
  • dynamic longitudinal gap acceptance during lane changing

This model is activated using the option --lateral-resolution <FLOAT>. The model is described in Simulation framework for testing ADAS in Chinese traffic situations in proceedings of SUMO2016

New Parameters

The vehicle behavior is subject to model-specific vType attributes (maxSpeedLat, minGapLat, latAlignment) and lane-changing-modell attributes (lcSublane, lcPushy).

Model Details

The regular lanes of the road network are divided into sublanes with a minimum width of the given resolution (--lateral-resolution). If the lane width is not a multiple of the given value, the leftmost sublane has a reduced with. The default lane-width of SUMO is 3.2m so a lateral resolution of 0.8 will created exactly 4 sublanes of that width per lane. A resulution of 1.0 will create three sublanes of 1.0m width and on more lane of 0.2m width. It is recommended use a resolution that is at least as small as the least wide vehicle being simulated (i.e. motorcycles).

Car-Following

Vehicles occupy one or more sublanes and perform car-following calculations for all vehicles that are being followed on at least one sublane.

Lane-Changing

The lane-changing model SL2015 is automatically used when enabling the sublane model. Lane-changing takes place at the sublane level and potentially uses the whole width of the road according to the width of the vehicles. Besides changing for route-following, cooperation, obligation (keepRight) or speed gain, vehicles also perform lateral movement to achieve a certain lateral alignment. This preference for either staying in the middle of a lane or to one of its sides is configured with the vType attribute latAlignment.

In addition to these motivation, an additional behavioral layer is responsible for maintaining safe lateral gaps. The desired gap can be set using the vType attribute minGapLat. Distances keeping is only performed in regard to vehicles that are not too far behind the ego vehicle. If the front bumper of a neighbouring vehicle is behind the longitudinal midpoint of the ego vehicle, that neighbour is ignored.

The model SL2015 supports these additional parameters:

• lcSublane: The eagerness for using the configured lateral alignment within the lane. Higher values result in increased willingness to sacrifice speed for alignment. default: 1.0, range [0-inf]
• lcPushy: Willingness to encroach laterally on other drivers. default: 0, range [0-1] If this is set, vehicles will start to change laterally even though their target sublanes(s) are still occupied. For urgent (strategic) lane-changes this produces behavior where the ego vehicle violates the lateral minimum gap of its neighbor and thereby triggers evasive lateral movement (pushing).
• lcAssertive: Willingness to accept lower front and rear gaps on the target lane. default: 0, range 0 to 1
• lcImpatience: dynamic factor for modifying lcAssertive and lcPushy. default: 0 (no effect) range -1 to 1. Impatience acts as a multiplier. At -1 the multiplier is 0.5 and at 1 the multiplier is 1.5
• lcTimeToImpatience: Time to reach maximum impatience (of 1). Impatience grows whenever a lane-change manoeuvre is blocked.
• lcAccelLat: maximum lateral acceleration per second. Together with maxSpeedLat this constrains lateral movement speed.

Misc

Vehicles can be located laterally anywhere on the lane(s). Vehicles change lanes incrementally depending on their maxSpeedLat vType-attribute. The width of sublanes affects the fidelity of car following in regard to the acceptance of lateral gaps and also determines the number of candidate movements that are evaluated during lane-changing.

When controlling vehicles via-TraCI using the vehicle command moveToXY, vehicles will be placed at the exact longitudinal and lateral position to match the specified coordinates. This allows for full control of sublane-placement.