Only olive green and the really, really dark green (rarely used on a sprint and typically indicates something that your REALLY cannot cross e.g. a hedge) are greens that you aren't allowed in. Any other shade of green just indicates the vegetation thickness and you can run through it. Bear that in mind if you end up running at Garvey Park because it has all shades of green on it - there is one tiny hedge that I've used impassable green on but you shouldn't encounter it.
yeah im new to sprint stuff so still learning all these silly passable/non-passable rules.
Yeah much different to standard bush or Metro events where you can go over/through it if you really want to!
Mind you there was a symbol for earth bank in the legend that says impassable that I'd have not taken for impassable. It doesn't look all that different from the one in the standard legend below it that you can pass.