Sportive / participation rides: how many marshals?

First off, ride the route yourself Mike. While you're doing it have a think about what it would be like if you didn't know the route. You'll probably find that you would want someone to tell you when you're approaching a point of potential danger - major junctions, blind bends etc. One tip if resources allow is to have a couple of riders from your club ride each route on the morning of the event well before the first rider starts. Make sure they have phones with them so they can report on any issues on the day. For instance - last Sunday I was pre-riding the route of our club sportive, went round a roundabout and ended up on the deck - the newly-laid surface had turned it into an ice rink. One call to HQ and I had another rider going out to the spot I was supposed to be marshalling, I'd re-allocated myself to marshalling the roundabout of doom, and the ambulance was sent out to sort my knee out while I made sure that riders really, really did slow down. Good luck sorting it all out.

i'd prioritise the intersections where there's a potential safety issue:

- turning right off a main road
- turning onto a main road
- poor sight lines
- feed stations

and anywhere else there's a possible issue. rank them according to the risk and assign marshals accordingly. junctions are more problematic near the start when the riders are more closely grouped. make sure you've got enough to cover the real problem sites and then you can send the others to lesser spots if you have more

O rly? tell that to the stewards / marshalls who a white van driver drove at and very nearly ran over and killed / murdered them, saw it all with my own eyes...

This was all in full view of many police who were over to him and surrounded the vehicle in a shot.

No doubt nothing serious was done but hey ho.

From my point of view I think you only need Marshals at the Start and Finish and then a points of potential danger (level crossings, steep twisting hills, busy road junctions, feed stations). Otherwise sign posting needs to be obvious and unambiguous.