lane markings - widths and lengths and colours

Manual on uniform traffic control devices
(source)

Section 3A.05 Widths and Patterns of Longitudinal Pavement Markings

Standard:
The widths and patterns of longitudinal lines shall be as follows:

1. A normal line is 100 to 150 mm (4 to 6 in) wide.
2. A wide line is at least twice the width of a normal line. The width of the line indicates the degree of emphasis.
3. A double line consists of two parallel lines separated by a discernible space.
4. A broken line consists of normal line segments separated by gaps.
5. A dotted line shall consist of noticeably shorter line segments separated by shorter gaps than used for a broken line. The width of a dotted line shall be at least the same as the width of the line it extends.

Guidance:
Broken lines should consist of 3 m (10 ft) line segments and 9 m (30 ft) gaps, or dimensions in a similar ratio of line segments to gaps as appropriate for traffic speeds and need for delineation.

Option:
A dotted line for line extensions may consist of 0.6 m (2 ft) line segments and 0.6 m (2 ft) to 1.8 m (6 ft) gaps. A dotted line for lane drop/add markings may consist of 0.9 m (3 ft) line segments and 2.7 m (9 ft) gaps.