What do you call someone who commits a traffic violation?

Solution 1:

You could consider using habitual traffic offender for someone who habitually commits those violations you mentioned. According to Washington State Department of Licensing (reference is not available on California DMV), it is defined as:

A driver who, within a 5-year period, has been:

Convicted of 3 or more offenses listed in RCW 46.65.020(1).

or

Found to have been convicted of or committed 20 or more moving violations listed in WAC 308-104-160. The violations must have occurred within a 5-year period. If more than 1 of these offenses are committed within a 6-hour period, they’re only counted as 1 on the first occasion.

The Law Place defines it as:

... and receiving 15 or more moving violations within five years.

Moving violations:

A moving violation is any violation of the law committed by the driver of a vehicle while it is in motion. The term "motion" distinguishes it from other motor vehicle violations, such as paperwork violations (which include violations involving automobile insurance, registration and inspection), parking violations, or equipment violations.

[Wikipedia]

Solution 2:

I'd suggest, minor offender.

minor offense: noun A criminal infraction less serious than a misdemeanor. These infractions may not even be tracked as part of a criminal record, depending on state and local laws. Generally, these types of infractions carry penalties of monetary fines and/or up to 90 days in jail. Depending on the state and local statutes, an example of a minor offense is a parking violation or traffic (driving) offense. YourDictionary

In light of your edit, consider [minor] traffic scofflaw.

scofflaw:

One who habitually violates laws, especially laws that do not involve serious criminal offenses. AHD

A contemptuous law violator M-W

Traffic scofflaws run the risk of getting ticketed, or even losing their license, because they constantly ignore traffic laws.

Solution 3:

You may call this person a misdemeanant. Definition:

A person convicted of a misdemeanor or guilty of misconduct.

Definition of misdemeanor:

A minor wrongdoing.

You may also call this person an infractor. Definition:

One that infracts or infringes: violator, lawbreaker

(Oxford Dictionaries Online: misdemeanant, misdemeanor)

(Merriam-Webster: infractor)