Vehicle traveling control apparatus

1. A vehicle traveling control apparatus for a vehicle, the vehicle traveling control apparatus comprising:

a cruise control configured to keep the vehicle traveling at a constant speed in accordance with a target speed without an accelerator pedal operation by a driver;

an operating lever which is operated by the driver to increase or decrease the target speed to an arbitrary value;

at least one processor programmed to:

acquire a speed limit of a road on which the vehicle travels;

display the target speed and the speed limit on a display device;

perform a first function to increase or decrease the target speed by a predetermined change amount every time a certain time elapses while a push operation of the operating lever continues after a long-push operation is detected, and a second function to set the target speed to the speed limit when the long-push operation of the operating lever is detected, the long-push operation being a push operation of the operating lever which continues for a long-push completion time;

acquire a speed deviation which is a magnitude of a deviation between the speed limit and the target speed;

set the target speed through the first function when the speed deviation is equal to or smaller than a predetermined threshold which is larger than zero at a time point at which the long-push operation is detected; and

set the target speed through the second function when the speed deviation is larger than the threshold at the time point at which the long-push operation toward a side bringing the target speed closer to the speed limit is detected.

2. The vehicle traveling control apparatus according to claim 1 ,

wherein, when the target speed is set through the first function, the processor is further programmed to:

increase or decrease the target speed by the predetermined change amount in such a manner that the target speed becomes one of multiples of the predetermined change amount; and

set the target speed to a value which is closest to one of the multiples in a changing direction of the target speed, if the target speed at a time point of starting the push operation of the operating lever is not one of the multiples, and

wherein the threshold is set to be a value which is the same as the predetermined change amount.

3. The vehicle traveling control apparatus according to claim 1 , wherein the at least one processor is further programmed to:

change the threshold to one of values including at least zero in response to an operation of the driver.

4. The vehicle traveling control apparatus according to claim 1 , wherein

the operating lever is configured to perform a function to stop the cruise control in response to an operation of the driver, and perform a function to restart the cruise control which has been stopped, in response to an operation of the driver, and

the at least one processor is further programmed to:

store the target speed at a time point at which the cruise control is stopped;

set the target speed at a time point at which the cruise control is restarted to the speed limit, when the cruise control is restarted in response to the long-push operation of the operating lever; and

set the target speed at the time point at which the cruise control is restarted to the stored target speed, when the cruise control is restarted in response to a short-push operation of the operating lever which is a push operation which is terminated before the long-push completion time elapses.

5. The vehicle traveling control apparatus according to claim 1 , wherein the at least one processor is further programmed to:

display on the display device an operation instruction indicating operation procedures of the operating lever for setting the target speed to the speed limit; and

prohibit display of the operation instruction when the speed deviation is equal to or smaller than the threshold.

6. A vehicle traveling control apparatus for a vehicle, the vehicle traveling control apparatus comprising:

at least one processor programmed to control a driving force and a braking force of the vehicle in such a manner that a vehicle speed of the vehicle does not exceed an upper speed limit;

an operating lever which is operated by the driver to increase or decrease the upper speed limit to an arbitrary value,

wherein the at least one processor is further programmed to:

acquire a speed limit of a road on which the vehicle travels;

display the upper speed limit and the speed limit on a display device;

perform a first function to increase or decrease the upper speed limit by a predetermined change amount every time a certain time elapses while a push operation of the operating lever continues after a long-push operation is detected, and a second function to set the upper speed limit to the speed limit when the long-push operation of the operating lever is detected, the long-push operation being a push operation of the operating lever which continues for a long-push completion time;

acquire a speed deviation which is a magnitude of a deviation between the speed limit and the upper speed limit;

set the upper speed limit through the first function when the speed deviation is equal to or smaller than a predetermined threshold which is larger than zero at a time point at which the long-push operation is detected; and

set the upper speed limit through the second function when the speed deviation is larger than the threshold at the time point at which the long-push operation toward a side bringing the upper speed limit closer to the speed limit is detected.