Modal Split and Its Implication

Gachanja (2011) carried out modal split modeling in Flowmap (software/programme) with

APEC engineering consultants, 2010) and are given as Table 5; the rates were used to convert the person trips to vehicle trips.

Table 5: Average occupancy rates and PCU factors for vehicles in Nairobi

Mode Occupancy PCU (passenger car unit)

Car 2.2 1.1

Public transport ^{12.5 2.5}

Source: MRTS report CES and APEC, 2010

Table 6 presents the number of private car trips and public transport trips that are originating from and that are destined to the respective TAZs. The results are aggregated according to administrative units of divisions in Nairobi city.

From the results, the largest number of private car O-D flows were recorded in Embakasi Division followed by Central Division then third was Kasarani Division. The lowest number of private car flows was recorded in Pumwani Division. In terms of the Public transport, the largest flows were recorded in Embakasi Division followed by Central Division, third was Kasarani Division. The lowest public transport flows were found in Pumwani Division.

Although the probability of trip makers using private car mode was 15 percent, it was less than the probability of using public transport which was 36 percent. The total private car trips stood at about 592,000 and were more than the public transport trips which totaled 570,000.

The reason for this result is that the public transport modes of transport have a higher mean vehicle occupancy rates (12.5 person trips) than that of private car modes of transport (2.2 person trips), hence they accommodate more travelers/trips).

Table 6 shows that there are an aggregated private car trips of about 59,000 and public transport trips of about 57,000 from Westlands. At a higher level of detail (per zone) there are of course variations with some zones such as Runda and Spring Valley having higher proportion of private car trips than other zones such as Parklands, Westlands centre, Gigiri and Kilimani which have higher proportion of public transport trips.

It should be noted, however, that although aggregately the number of car trips almost balances with the number of public transport trips for Westlands, more than five times the number of cars are required to transport the same number of commuters moved in public service vehicles due to the higher average capacity of public service vehicles (12.5 person trips) compared to the low average capacity of cars (2.2 person trips). With the new policy to introduce (through licensing) only high capacity public service vehicles which will raise the capacity to at least 30 person trips, even less number of public service vehicles will be required to make the same number trips. This is capable of not only appreciably reducing congestion on the roads and neighbourhood commercial centres in these zones but also reducing the strain and pressure on transportation facilities and infrastructure. The challenge is to provide quality and adequate public transport facilities, vehicles and services that will be attractive to high and middle class citizens living and/or working in these zones of study.

There must also be created efficient connections and accessibility to other areas of the city and the Nairobi Metropolitan Region for efficient and convenient movement with public transport services.

Table 6: Number of private car and public transport trips by O-D in NMR-2010

Administrative unit (TAZ) Private car trips/flows Public transport trips/flows Originating from Destined to Originating from Destined to Nairobi city divisions/TAZs

Central (CBD) 112679 115970 108172 111331

Makadara 51939 52181 49862 50093

Kasarani 81139 79452 77893 76274

Embakasi 135667 134996 130240 129596

Pumwani 45264 45545 43453 43723

Westlands (study area) 59013 59341 56653 56967

Dagoretti 55631 56529 53406 54268

Kibera 51010 51347 48970 49294

Total Trips 592343 595360 568649 571546

Source: Gachanja, KIPPRA, 2011

The household survey carried out by the study team gives the times when the majority of the household members leave their residences as Tables 7 and 8. It is clear that the majority (95.9%) leave between 6.00 and 8.00 hours for zones 3, 4 and 5. The time of coming or return in the evening is peaked between 18.00 and 20.00 hours with 84.8% for zones 3, 4 and 5. This implies that with high level of car ownership (as shown in Tables 9), the peak hour congestion and stress and strain on transport facilities in very high and is likely to continue to increase.

Table 7: Times of Departure for the day

Time of departure/leaving origin Trips leaving for zones 3,4 and 5

Before 6.00 hours 2.1%

6.00 – 8.00 hours 95.9%

After 8.00 hours 2.0%

% Total 100.0%

Table 8: Times of Return after the day

Time of Return/coming in to origin Trips coming in: zones 3,4 and 5

Before 18.00 hours 9.7%

Table 9: Car Ownership in the study area Number of cars

Proportion of households in car ownership: zones 3,4 and 5

0 1.0% destinations (and yet the number of cars owned is limited) or when there are problems with the household vehicles. In these cases, the alternative modes of travel that would be used by household members are as given in Table 10.

Table 10: Alternative modes of travel used by households in the study area Alternative

The results in Table 10 give different possibilities and strategies of handling transportation of households in the study area. The majority obviously use one clear alternative, namely, public transport system. There are other means of travel that can be explored and encouraged by developing appropriate facilities and infrastructure (which is currently non-existent or poor in state); these include facilities for pedestrians and other non-motorized transport modes. There is also need to streamline the use of motorcycles and bicycles (boda bodas) as modes of public transport in the city. They are currently being used informally and have been a great concern, especially due to safety and security reasons.

The households in zones 3, 4, and 5 have explored a number of alternative means of transport. This presents opportunities for introducing more alternatives of movement and travel that are likely to be acceptable to the residents, including efficient public transport and non-motorized transport for short trips.