The way we are meant to cross the Gogar Roundabout safely is via Family Network Route 9 around the North side.
Heading East you once you have survived the other problems with the other problems with the A8, you have a slight downhill with an unexpected sharp corner on (which caught Snowy out) and cross Turnhouse Road and on to the Toucan to cross Maybury Road (It is a Toucan Snowy).
Best thing now is to turn left and head along North Gyle Terrace to Dechmont Road. (It is a shared use path along the Northside of Glasgow Road but most people ignore this - it suffers from lots of driveways with priority).
The problem is that most people don't want to bimble along Route 9 but want to get onto the Glasgow Road proper.
Therefore the common route is to exit the path at the entrance of new Gogar Station Building site and take your chances with the 'blender' of 4 lanes mixing up into 2. Not for the fainthearted.
Similarly westbound you get a similar problem. Route 9 is fine if you have the time, but most people are already on Glasgow Road and the question is when to get off.
The Toucan crossing at the Jaguar garage is probably safest but you have to wait a long time for them to work.
Next option is turn right at the Maybury Road traffic lights, but the sequencing is such that a long straight on sequence is followed by a short right turn. This means that if you approach when they are on red, it is easier to cross the 2 lanes of straight on traffic but you are then waiting ages for the right turn. If you approach when it is green for straight on then your wait will be quite short but it is very difficult to get across the lanes.
A common response is to stay in the left lane and take your chances going up the slope to the roundabout proper and heading straight across from the right hand lane. Takes a bit of traffic dodging but infinitely preferable to taking the underpass.
My current route of choice is to go onto the Southern pavement at the Marriott and follow that round to Gogar Roundabout, where you have to play leap frog over the 2 sets of queuing traffic trying to enter the Gyle. I then take the exit route from the Gyle onto the Roundabout and head across to A8 westbound exit (this saves having to play frogger directly with the traffic on the bypass (3 lanes then 4 lanes!)). Once exiting the roundabout I return to the southbound path.
The only risky bit with this is having a vehicle following you onto the Gogar Roundabout as they want to race through the next green light but experience has told me I can never make it (and most of the time they can't either) so I take it fairly easy setting off.
A complete guddle is a good description. On the bright side CEC have alotted £150k (& Sustrans matching it) for Gyle/Newbridge "Crossing improvements, resurfacing & signage", but I don't expect they will tackle Gogar.