Just to add to the debate, here is the California vehicle code section that covers this subject:
23109. (a) A person shall not engage in a motor vehicle speed
contest on a highway. As used in this section, a motor vehicle speed
contest includes a motor vehicle race against another vehicle, a
clock, or other timing device. For purposes of this section, an
event in which the time to cover a prescribed route of more than 20
miles is measured, but where the vehicle does not exceed the speed
limits, is not a speed contest.
(b) A person shall not aid or abet in any motor vehicle speed
contest on any highway.
(c) A person shall not engage in any motor vehicle exhibition of
speed on a highway, and no person shall aid or abet in a motor
vehicle exhibition of speed on any highway.
(d) A person shall not for the purpose of facilitating or aiding
or as an incident to any motor vehicle speed contest or exhibition
upon a highway in any manner obstruct or place a barricade or
obstruction or assist or participate in placing a barricade or
obstruction upon any highway.
23109. (a) A person shall not engage in a motor vehicle speed
contest on a highway. As used in this section, a motor vehicle speed
contest includes a motor vehicle race against another vehicle, a
clock, or other timing device. For purposes of this section, an
event in which the time to cover a prescribed route of more than 20
miles is measured, but where the vehicle does not exceed the speed
limits, is not a speed contest.
(b) A person shall not aid or abet in any motor vehicle speed
contest on any highway.
(c) A person shall not engage in any motor vehicle exhibition of
speed on a highway, and no person shall aid or abet in a motor
vehicle exhibition of speed on any highway.
(d) A person shall not for the purpose of facilitating or aiding
or as an incident to any motor vehicle speed contest or exhibition
upon a highway in any manner obstruct or place a barricade or
obstruction or assist or participate in placing a barricade or
obstruction upon any highway.