Sister isle needs new traffic rules

The Association of Professional Engineers of Trinidad and Tobago (APETT) held a breakfast seminar on May 31, 2006 entitled “A Mass Transit System for Trinidad and Tobago.”

Mass transit, public transit, or public transport means the same.

There was no representative from either the Ministry of Works and Transport (MWT) or Parsons Brinckerhoff (PB), Consultant for both the Comprehensive National Transport Study (CNTS) and the Trinidad Rapid Rail Project (TRRP).

A letter from Minister Colm Imbert was read by newly- elected APETT President, Mark Francois, which sought to explain that the process for the TRRP had already started and that he did not want to interfere with the project process, and so regretted that he could not attend.

If the Works Ministry and PB, who are the recommenders and perhaps implementers of the future form or forms of mass transit for TT, had attended they might have been re-educated in some ways. In the next few articles I will attempt to re-engineer the thinking and learning towards national mass transit suitable for socio-economic benefit.

Today, I focus on Tobago. On April 27, 2006 PB presented to key stakeholders their diagnosis of the transportation system in TT. They recognised that a comprehensive transport study was never ever done for the sister isle. PB showed that current traffic entering Scarborough during the morning peak hour is about 3,000 vehicles, and 2,700 vehicles exiting in the evening peak hour.

The average person occupancy of the vehicle would be 2.20 and 2.23 persons per vehicle, respectively. And the percentage share of public transport use (versus private car use) is 26 percent into Scarborough in the morning and 30 percent out of Scarborough in the evening.

The best current values in developed countries for the modal share of public transport range between 30 and 50 percent, and the acceptable range for developing countries is 50 to 70 percent. Therefore, current transit usage in Tobago is far below international benchmarks.

This writer has conducted independent mathematical modelling and analysis of journey-to-work travel patterns applying projected population and employment data from the Central Statistical Office (CSO). The results represent an order of magnitude of the existing person work trip demand between and within each of the seven parishes. The highest demands for travel occur in the Parishes of St Andrew and St Patrick, and as would be expected, the highest road traffic linkages are between these two zones.

According to the computation, the total number of persons wishing to get to work in the Parish of St Andrew, which has the town of Scarborough as the primary focus of land use activity, is of the order of 12,000. If it is assumed that government policy is to achieve 60 percent transit modal share, then transport planning has to provide for 7,200 persons wishing to get to work in the Parish of St Andrew from all the other parishes.

It is reasonable to assume that the peak morning work trips occur in Tobago within a two-hour period — 6.30 am to 8.30 am, and so the according to the PB study the total number of people entering Scarborough in the morning peak period would be in the range of 10,000 to 13,000 persons. Therefore, PB’s survey confirms the computation above.

Continuing with modelling, the Parish of St Patrick, with the village of Bon Accord as having the predominant land use activity, has to provide transit for the order of 4,000 persons wishing to get there for work from all over Tobago. Overall, there would be a need for transit work trips of the order of 15,200 persons, excluding the transport of schoolchildren.

There would be trips to work by transit from Bon Accord to Scarborough of about 1,900 persons, and trips to work from Scarborough to Bon Accord of about 1,200 persons, a distance of about 11 km. Therefore travel along Milford Road and the Claude Noel Highway with a journey time of about 30 minutes (including travel time, boarding and alighting), over a period of two hours, with 60 seated and standing in a bus, would need about eight buses on that route.

The current annual vehicle growth rate in TT is nearly ten percent, and this rate of growth is difficult to determine in Tobago because of the high number of vehicles arriving and departing by ferry for occasional (often daily) use in Tobago. The island also has a small number of two-lane primary and secondary roads, and there is obviously a limited amount of road capacity and expansion possibilities, with the island size being only 300 sq km.

The Claude Noel Highway is a primary arterial road with a two-lane single carriageway, with each lane having 3.65 m width, and paved shoulders of 2.4 m width, for a total roadway width of about 12.1 m. Its design speed is 80 kmph and posted speed limit is 50 kmph. PB has shown that the current operational speeds on this road range between 40 and 80 kmph.

The current vehicle occupancy (average of 2.20 persons per vehicle) is unsatisfactory, if management of the limited road space is to be sustained. Provision of transit for only 15,200 persons going to work in an entire island is not difficult, and can be sustained with minimal government intervention by way of operations, but not without government planning and administration.

I hope that government technocrats are not running off considering major road widening and expressways, or worse, light rail transit between Crown Point and Scarborough, as these would be extreme solutions done in the absence of scientific analysis. The most effective solutions lie with travel demand management.

e-mail: lfsystems@carib-link.net