Taxi Confusion in Singapore - Varying flag down fares, distance charges and models

Probably the most complaining part about taxi is the 'non-availability' when one really needed. For example, during peak hour or when its raining. However I have another issue with taxi which I encountered during my trip from Changi couple of days back. 

The challenge is the different models and the fare difference. I remember Straitimes did a great job trying to put things together in single file (I've uploaded here) and appreciate the effort.

What I did is to do a quick comparison with Excel assuming three different routes. I have taken plenty of assumptions and please don't ask me that how come your fare is much higher :) Reason is I've excluded any ERP charges, late night charges, location based charges, Peak hour charges, booking charges, waiting charges and all other stuff. A very basic and simple calculation for the distance.

As you can see the price difference between the most common taxi (I guess Sonata) vs the most common Merc is huge. It's almost 38% difference.  That's excluding Crowns and the notorious Chryslers. 

The worst thing is the price difference between Sonata and Premier Kia. That's a 5% difference but in my experience taking this last week was a difference of 30%. Normally I pay 21-23 for a trip using Sonata and this time I ended up paying 26 which is quite huge difference. The traffic was smooth and the route is the same. No idea why and that motivated to write this in the first place. 

Even if we take the difference between Sonata - i40 from Comfort (largest operator) that's a difference of 50C but 5-8% higher depending on how long the commute is. No idea why and how the operators decide to charge, rise the fares. I recall LTA controls the fares just like the PTC for public transport but it seems these days the taxi operators have a free hand :|

I wish there is some commonality. Just remove the so many versions and keep two or three versions. 

1. For regular usage - Sonata, i40, Prius and all can go here
2. For Exec or Sedan - Merc or likes of it
3. MPV's - Larger groups .

That would simplify the fare confusion up to some extent. Ofcourse this doesnt answer the "peak hour surcharge, mid night surcharge, and location surcharges..