It was called another 'carmaggedon,' an evening many motorists and commuters left work one day and made it home the next. Only a select few were spared the ultra extended transit time but it was considerably longer than the usual, considering how bad it already is on an ordinary day.

App-based transport systems were in pretty high demand that evening and according to users, GrabTaxi's app kept coming up with "oops sorry no driver available."

Another user settled for Uber, which had available vehicles, but due to the conditions that night also had a major price surge. She booked a Black with a 2.8 price surge. The 7.7-kilometer trip took 1.5 hours and total price was Php 1,030.

She was one of the lucky few.

A GrabTaxi user reported that she finally booked a ride around 11PM after offering a generous tip only to find out that the driver agreed to pick her up because he was amenable to the destination.

GrabTaxi has received numerous complaints about how their service GrabCar failed to pick up passengers who booked rides that evening.

In a statement, GrabTaxi issued an apology and cited reasons why their service broke down.

"We would like to apologize to commuters as not everyone was able to get a ride home via our service during the downpour last Tuesday, 8 September 2015."

"Many of our drivers were affected and got stranded, like the rest of Metro Manila, and were not able to accept bookings as they were caught in the gridlock. The flooded road conditions also meant that they would have risked passenger safety and their cars breaking down."

In order to "increase the number of bookings accepted," GrabTaxi says an update is on the way "to improve the algorithm of matching demand and supply, particularly during peak hours. Currently, availability of drivers can be more accurate and we are further developing the app to address that."

Addressing the passenger experience, GrabTaxi promises to 'enforce stricter process of reprimanding drivers for the improper use of the app (i.e. not switching off app if unable to accept bookings) and remind them on the high service levels expected."

Also, GrabTaxi will look into the feasibility of the tip feature, taking into consideration how it affects pricing so that passengers will not be subject to "unreasonable fares." The app-based transport company argues that "the tip function allows us to balance out high demand during low supply situations without forcing passengers to pay a surge."

The question is, at what point does a tip become a bribe to book a ride?

GrabTaxi/GrabCar will discuss all of the feedback with the Land Transportation Regulatory and Franchising Board (LTFRB) in order to improve their service in the future.