The Rule: (a) This Rule applies to traffic separation schemes and does not relieve any vessel of her obligation under any other rule.

(b) A vessel using a traffic separation scheme shall:

(i) Proceed in the appropriate traffic lane in the general direction of traffic flow for that lane.

(ii) So far as is practicable keep clear of a traffic separation line or separation zone.

(iii) Normally join or leave a traffic lane at the termination of the lane, but when joining or leaving from either side shall do so at as small an angle to the general direction of traffic flow as practicable.

(c) A vessel, shall so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.

(d)(i) A vessel shall not use an inshore traffic zone when she can safely use the appropriate traffic lane within the adjacent traffic separation scheme. However, vessels of less than 20 meters in length, sailing vessels and vessels engaged in fishing may use the inshore traffic zone.

(ii) Notwithstanding Rule 10(d)(i), a vessel may use an inshore traffic zone when en route to or from a port, offshore installation or structure, pilot station or any other place situated within the inshore traffic zone, or to avoid immediate danger.

(e) A vessel, other than a crossing vessel or a vessel joining or leaving a lane shall not normally enter a separation zone or cross a separation line except:

(i) in cases of emergency to avoid immediate danger;

(ii) to engage in fishing within a separation zone.

(f) A vessel navigating in areas near the terminations of traffic separation schemes shall do so with particular caution.

(g) A vessel shall so far as practicable avoid anchoring in a traffic separation scheme or in areas near its terminations.

(h) A vessel not using a traffic separating scheme shall avoid it by as wide a margin as is practicable.

(i) A vessel engaged in fishing shall not impede the passage of any vessel following a traffic lane.

(j) A vessel of less than 20 meters in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane.

(k) A vessel restricted in her ability to maneuver when engaged in an operation for the maintenance of safety of navigation in a traffic separation scheme is exempted from complying with this Rule to the extent necessary to carry out the operation.

(l) A vessel restricted in her ability to maneuver when engaged in an operation for the laying, servicing or picking up of a submarine cable, within a traffic separation scheme, is exempted from complying with this Rule to the extent necessary to carry out the operation.

Discussion: This Rule is quite lengthy but students are best served by reading each element individually and slowly. 

First, what does a Traffic Separation Scheme look like? Here are a few images of schemes in the USA. The first image is the approaches to Chesapeake Bay, and shows a large precautionary area with northbound and southbound lanes exiting it.

The second picture is in Washington State and shows the Strait of Juan de Fuca, which features an inshore and an offshore traffic lane. 

These lanes are magenta on charts, have a magenta separation zone designated, and according to the rules should be followed by all vessels.  It is important to note that the rest of the Navigation Rules still apply in traffic separation schemes except where specifically described in this rule.

In general, the rule can be read as similar to the narrow channel rule (rule 9) in that fishing vessels, small vessels, anchored vessels, etc. should not impede the passage of vessels using the traffic lanes. Vessels should be particularly careful at the termination of lanes, because vessels will be approaching from a variety of directions and could increase the risk of collision. Each specific element of the rule illustrates certain restrictions that are important to study.

Other key points to this rule are that vessels should join traffic separation schemes at a shallow angle and should cross traffic separation schemes at a perpendicular angle. This is to best facilitate risk of collision in the lanes: joining vessels will be overtaking or be overtaken at shallow angles and crossing vessels will minimize their time in the lanes. 

Test Strategy:  There are about 10 questions in the database regarding traffic separation schemes and there are no differences between the inland and the international rules.