Travel Control System

A travel control system that controls automatic travel of a work vehicle that includes a work device, wherein:

• the work vehicle is configured to perform outermost periphery traveling by automatic travel, and the outermost periphery traveling is work traveling performed along an outer shape of an agricultural field in an outermost peripheral region of the agricultural field, and
• the outermost periphery traveling including first traveling for traveling in a first direction while driving the work device, second traveling for traveling in a second direction while driving the work device, and a direction change operation that is performed between the first traveling and the second traveling and is performed to change a direction of the work vehicle from the first direction to the second direction,
• the travel control system comprising:
• a permission unit configured to permit outermost periphery automatic traveling, which is the outermost periphery traveling performed by automatic travel, in response to at least one predetermined permission condition being satisfied;
• a prohibition unit configured to prohibit the outermost periphery automatic traveling in response to the permission unit not permitting the outermost periphery automatic traveling;
• and
• a threshold value determination unit, and
• wherein:
• the at least one permission condition includes a first condition and a second condition,
• the first condition is that a reference value corresponding to a working width of the work device is larger than a lateral width of the work device,
• the second condition is that the reference value is larger than a threshold value determined by the threshold value determination unit, and
• the threshold value determination unit is configured to determine the threshold value based on a reference distance between a front end position of the work vehicle and a reference position at which the work device is switched from a working state to a non-working state.