The SMT Conditions of Carriage (ie prior to selling off the National bus company for Scotland included Clause 7(d) On rural services operated by appropriate vehicles, bikes may be carried at the driver's discretion. Scottish Citylink (then operated as part of SMT) had Clause 10(d) Cycles are not carried but this was later modified with Clause 10(e) which permitted the carriage of folding bikes. I'll review the current position as I understand it after the brief history.
Of course the first advertised bike carrying bus service actually ran in Scotland in 1963, using an Alexander-bodied Leyland converted to carry cyclists and pedestrians across the Forth Road Bridge. I have found some pictures of the bus but not any really good ones of loading bikes
After the sell off, most new operators continued to use the Alexander Y-Type with a variety of chassis as the Scottish 'Routemaster' on most rural routes - with careful packing you can get 4 bikes in the rear locker on most of these buses, and I regularly used the 59 (Midland) to Callander and the 62 (Peebles/Glentress/Innerleithen) or the 95 (Edinburgh-Carlisle)
The Bikes on Buses Cycle Challenge 1996(DETR) and 1998(Sc)
In 1996 the project to test applications for external racks included a report by TRL on the practical and legal issues, and tested buses and coaches to ENCAP impact standards with pedestrian dummies (TRL 592). They rightly pointed out that with buses having the highest rate of pedestrian impacts of any class of vehicle on the UK and European road network, the stringent detail on having hard and sharp edges facing forwards made the use of US-style systems unacceptable, and the cost and complexity of delivering a front mounted unit the eliminated the problems and complied with the legislation would be a costly exercise, hardly likely to attract interest if no obvious gain in passenger numbers was delivered. For this reason, and the fact that since 1999 all new buses have had to be low floor, roll-on access, we have the potential for most operators to try-out cycle carriage on lightly used rural services (and possibly late night town routes for those who are not happy riding on routes they would use during the day), all for a minimal cost of some securing straps and protection against pedals etc bashing against a decorative panel surface.
Edinburgh-Glentress
The 62 presents a supreme irony as when Arthur Phillips was pioneering the use of Glentress for MTB activities and less than 5000 people per year went cycling there, you could pile up to 4 bikes on to the hourly 62 service and head own for the day. With the introduction of the 'accessible' (sic) buses and a 30 minute frequency at some times of day bikes are officially refused - and now nearly 100 times more people are going to Glentress*, but I did a family visit with 2 folding bikes and 2 kids bikes - cycling to 'bag' the Traquair House maze without any problems using a 'decker going out and a low floor bus coming back. A number of individuals also report a pragmatic approach by most drivers, after all, it works, and sells a few extra tickets, and the main office of First Lothian & Borders is a long way away in Camelon! One option is to operate some of the weekend services with coaches or consider a shopper/cyclist service using coaches to take shoppers to South Gyle/Edinburgh Princes Street from the Borders, and Cyclists to Glentress. Operators tak tent and consider registering such a route?
Bikes CAN go on coaches - especially Stagecoach Express
In 1998 I did a Bikes with coaches project and Stagecoach, and we made sure that their conditions of carriage were brought up to date (at the time it theoretically banned the carriage of wheelchair users in their wheelchairs despite the company having a substantial fleet of low floor buses by then). As a result you can get bikes on to most of the Stagecoach Express services, where coaches are used - that's how I got back on Sunday from St Andrews to Glasgow, how the kids from Banchory get in to Aberdeen to use the BMX track, and those in Elgin get out to Fochabers to use the Ben Aigen trails. You can avoid the hazards of the A75 by using the 500 or X75 between Dumfries and Stranraer, and the X74 stops at Parkgate, just a short ride from the Ae Forest. Hitrans does have large polythene sacks (also sold through CTC shop) that can be used to bag up a bike and meet the requirement that no damage or soiling of the coach hold or other items in it comes from a wet or dirty bike. I also hear of pensioners, in Moray especially using their bus passes to go upwind/uphill and ride back. During the summer you can also enjoy the 501/502 services which start from Aberdeen (as the Ballater service-201) and travel on alternate days to Perth, via Blairgowrie or Aberfeldy via Pitlochry, and return. First also operate with coaches on some Central Scotland routes - mainly to Livingston/N Lanarks from Glasgow. One of the very popular route South of the border is the Oxford Tube with 3-5% of passngers on the peak commuter journeys taking a bike on the coach with them.
Long Distance trips - Including Galashiels.
For long distance travel the wording the we settled on with National Express now seems to be generally accepted, that bikes which are dismantled or folded down to pack flat as luggage and covered or wrapped in a bag or case are normally accepted within your luggage allowance, on National Express, Scottish Citylink, First Greyhound, and Megabus (the last having a rather useful late night departure from Edinburgh on Saturday nights, and with National Express (383 Edinburgh-Wrexham) Megabus also runs a service via Galashiels (biggest annoyance is tha none of these operators provide an overview of the timetables to help intending passengers make an informed choice
One caveat when using coaches and underfloor holds, is that you should join and leave the service at a min stopping point, the driver may refuse to let you on or off at the roadside on safety grounds.
Bus services also carry bikes and here is where a Scotland-wide lobby would really be useful. Western isles Council has, as the default condition on all of their subsidised bus service contracts, a requirement that cycles are carried (obviously this would exclude times when every seat is needed for the school or commuter service) Hitrans has made this a condition for some supported services elsewhere, notably (since 2007) the service that connects 3 ferry piers in Argyll with Lochgilphead (and saves a stiff climb from Cloanaig)
Hendersons have generally been OK and the bus from Hamilton to Strathaven can be a great way to get home when the night is foul, windy and wet, but obviously you won't be popular when its filled with commuters. I've also noted the Stagecoach services coming back in from Pitlochry and Aberfeldy at night - often empty but still in service to get them back to the depot in Perth - potential here to have a full day out -taking 2-4 bikes inside on the empty bus going to collect the local folk for work, school or shopping, and coming back on the late one.
I've got pictures, data etc going right back to 1986 when I was using the 59 almost weekly to get to Sustrans sites around Callander, and the carriage counts for US systems that used to be collated (when only a few bus operators did this) typically a 2-4% boost in patronage but often a substantially greater boost to the off-peak services the bikes tend to use.
Some key routes?
Girvan to Newton Stewart (Glentrool/Kirroughtree) a contracted service (include bike carriage in contract)
Tay/Tummel Valley-Perth noted previously
Carlisle-Newcastleton local operated - Telfords in some contracted with Cumbria CC leading authority
Loch Lomond National Park - several
Spey Valley - link with Spey Valley Way
I'm going to flag this with those who might be able to deliver so if you have suggestions to refine that last list .....
East Neuk - general on all local routes at weekends?