CDOT continues to push this transit solution because of its ability to have buses start and complete their trips from outside the guideway.  I have always been curious about the ability of buses to enter and exit the guideway without an overlaying interchange, (that is a separate interchange at every exit to allow the buses to enter and exit the guideway from local roads without interfering with the entering and exiting traffic from the general travel lanes).  CDOT maintains that an overlaying interchange for the bus guideway would be very expensive, (and they're right!).  This alternative was not priced out with overlaying interchanges as a result.

 

In Appendix E Page 7, the mechanism for the buses to enter and exit the guideway minus interchanges is provided. This information is not provided in Chapter 2, pages 2 - 36 through 2 - 38 under the description of the Bus in Guideway alternative, (although the Route Structure map assumes that the buses can enter and exit the guideway at will).

 

 

 

 

 

One operational issue to be resolved would be the operation of the dual-mode buses through the gaps.  Initial typical sections assumed that power would be supplied from the outside wall of the guideway (between the guideway and general traffic), while a short median barrier would be provided between the two-guideway tracks for guidance only.  With this design, the buses would have to briefly switch into diesel mode to cross each gap.  Alternately, the inside median could be redesigned to provide power, at least for the duration of the gap.   

 

Clearly CDOT has not worked out the detail for these gaps and how slow moving buses, (especially on hills) will interfere with the general travel lanes as they enter or exit the guideway from what will essentially be a left lane, (occupied by speeding motorists).  Snow removal will continue to present a problem for this alternative both inside and outside the guideway and especially in the areas of the gaps.  The gap solution does however answer the question I had about why the bus guideway must be median located. 

 

My view of the dual mode bus would be more similar to an on line transit system with the ability to travel short distances outside the Corridor on relatively mild grades.  Sixty passenger dual mode buses, while perhaps faster in the guideway will be real slugs on diesel power alone outside the guideway and will have a very difficult time with mountain passes like Berthoud, Loveland or Vail.  Suggesting that dual mode buses would have to switch to diesel power every few miles to pass though gaps at interchanges is also concerning.  This cannot be a practical solution. 

 

For travel outside the guideway, a diesel bus will be a better choice, however ridership numbers for diesel buses are not exactly dramatic.  I think that this alternative has some significant issues to be resolved that will affect its future in the PEIS selection process.