The District of Columbia and Maryland both take part in the Drivers License Compact and thus DC's court or DMV will inform the Maryland Motor Vehicle Administration of your mother's ticket in DC. Making a lane change without caution in DC would be a 2 or 3point offense.

The newly updated MD Motor Vehicle Administration site notes that if you are convicted of a vehicle-related offense in a jurisdiction outside of Maryland, the MVA may assess points. The point values identified in Maryland law for similar offenses determine the number of points that you will be assessed.

The types of out-of-state violations for which points may be assessed in Maryland according to the MVA include:

• Alcohol or drug related offenses;
• Leaving the scene of a personal injury accident;
• Homicide or manslaughter involving a vehicle;
• Use of a motor vehicle in the commission of a felony.

The Maryland driver's manual currently states that once the MVA receives ticket information from another state they treat it as if the violation occurred in state. If that is the case, even if the offense is not one that they assign points to, it will be placed on your Maryland driving record.

If this DC moving violation is assigned points in Maryland it would be appear to only be one because it is not listed on the points list. The points lists states that any moving violation not specifically listed and did not contribute to an accident is worth 1point. To find out for certain if this out of state offense will put points on your mother's license contact the MD MVA.