Trackless trams are the new kid on the transport block. The mayor and a Wellington ward candidate are pushing for their adoption from the airport to Karori. Given that the transport package our Mayor recently released had no mention of Karori, it's bizarre for this to suddenly be on the cards. Like unicorns, pink elephants, and other things that don't really exist, trackless trams are hard to criticise, but I'm going to do my level best.
Indeed the fact they don't exist in any real way is what is appealing to people. People can project whatever they like onto the idea. If you're a car person, a trackless tram is just like a big bus, and probably won't have any road space prioritised over your needs. If you are a public transport person, a trackless tram gives you all the benefits of light rail at a fraction of the cost. Basically people can project whatever they want onto the idea, and because it doesn't exist you can't tell them they're wrong.
The big problem though is that the trackless tram debate almost misses the point, particularly in Wellington. The hardest challenge of getting rapid mass transit to the Airport is allocating two lanes from Wellington station to the airport. Regardless of the technology the transit needs to run separate from traffic. Taking road space from cars will be the most difficult political challenge. This is true for Bus Rapid Transit, trackless trams and light rail. As to transit to Karori, there are genuine concerns there, but given that transit to the airport is not currently scheduled until the 2030s, the idea that there will be trackless trams operating to Karori by 2022 is pure fantasy.
Really if you are going to bear the political challenge of genuine rapid transit, then the rest of the project will take care of itself, regardless of the technology. While I am not completely against trackless trams, I think proven technologies are better solutions.