Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis 4 Strategic Modelling Forecasts – Base This section describes the conditions of travel in the regional generally and between Porirua and the Hutt Valley in particular. Its purpose is to present a rationale for the network interventions described in Section 2. It achieves this by documenting model forecasts for the base 2006 to 2026 scenarios using the assumptions described in Section 3. It provides a summary of changes in demand pressures and network performance both at an aggregate level and at key locations. Those network performance measures are listed below: • Trip distribution change; • Traffic flows at key locations around the Hutt Valley to Porirua Corridor; • Volume capacity analysis both at an aggregate and localised level; and • Travel times between town centres in Porirua and Lower Hutt. May 2011 Issue 2 11 Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis 4.1 Trip Demand and Distribution Changes This section reports modelled two hour sector to sector demand changes between 2006 and 2026. It shows: • How trip distribution is forecast to change under base forecast scenario assumptions. For example, increasing highway congestion and travel times can cause some people to reduce the distances they are prepared to travel; and • The overall level of demand for travel for the main areas in questions: Hutt Valley and Porirua. Trips to and from Wellington have also been added due to the influence it has on commuter traffic from Porirua and the Hutt Valley. Heavy Commercial Vehicles (HCV) and car trips have been added together in the following three tables (Table 4-1, Table 4-2, and Table 4-3) presenting sector to sector movements across the AM, IP, and PM Peak base models between 2006 and 2026. The results are summarised below: • Table 4-1 shows a 23% overall increase in trips between 2006 and 2026 in the AM Peak. In terms of key movements relevant to this study, the largest growth in sector to sector demand is from Wellington to both Porirua and Lower Hutt –28% and 30% respectively. There is no growth in demand in trips from Lower Hutt to Porirua while trips from Porirua to Lower Hutt only grow by 8%. This is likely to be a function of low growth in population in Lower Hutt and Porirua and connections that have reached capacity (Ngauranga Interchange and SH58). • Table 4-2 shows a 23% overall increase in trips between 2006 and 2026 in the IP Peak. In terms of key movements relevant to this study, the largest growth in sector to sector demand is from Wellington to both Porirua and Lower Hutt (+23%). Trips between Porirua and Lower Hutt (both directions) are forecast to grow by between 10% and 9% respectively. Trips to Wellington from Lower Hutt and Porirua are forecast to rise by between 18% and 20% respectively. • Table 4-3 shows a 20% overall increase in trips between 2006 and 2026 in the PM Peak. In terms of key movements relevant to this study, the largest growth in sector to sector demand is from Lower Hutt to Wellington (+22%). Trips from Porirua to Lower Hutt are forecast to decrease by 2% and trips from Lower Hutt to Porirua are forecast to increase by 7%. Trips to Wellington from Lower Hutt and Porirua are forecast to rise by between 22% and 23% respectively. May 2011 Issue 2 12 Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis While the pattern of traffic remains focussed on Wellington one of the more interesting conclusions to draw from the above analysis is the forecast growth in both Porirua and Lower Hutt as key attractors, with some of the largest increases being: • Trips going from Wellington to Lower Hutt and Porirua in the AM Peak; • Trips going from Porirua and Lower Hutt to Wellington in the PM Peak (ie return trips); and • Trips between Lower Hutt and Kapiti also show some high growth rates and these are some of the trips that can switch from the current SH1/SH2 and SH2/SH58 corridors to the new Petone-Grenada Link. • As employment has been assumed to grow significantly faster than population in Porirua and Lower Hutt some of these new workers will need to travel from areas where there is greater population growth. Modelling undertaken in this study indicates that a significant portion of them could come from Wellington (one of the fast growing population centres). May 2011 Issue 2 13 Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis Table 4-1 : AM Change in Vehicle Trip Distribution 2006-2026 AM 2006 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South UpperHutt Wellington Total Grand Carterton 1,352 53 8 24 669 7 241 41 48 2,442 External 41 - 991 52 351 87 9 25 143 1,700 Kapiti 12 923 12,274 312 16 664 14 150 1,060 15,425 Lower Hutt 59 35 191 25,309 85 810 63 1,466 6,079 34,097 Masterton 425 235 8 31 8,067 7 168 58 72 9,070 Porirua 20 55 502 1,042 28 10,173 20 414 3,802 16,058 South Wairarapa 415 34 17 74 578 19 1,475 119 112 2,843 Upper Hutt 128 25 118 1,841 191 428 138 8,507 1,487 12,862 Wellington 45 50 399 4,266 81 2,392 62 687 63,189 71,170 Grand Total 2,498 1,411 14,507 32,951 10,065 14,586 2,190 11,468 75,992 165,668 AM 2026 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South UpperHutt Wellington Total Grand Carterton 1,562 52 13 36 785 11 266 61 60 2,846 External 43 - 1,208 75 435 107 9 34 140 2,051 Kapiti 25 1,177 15,804 504 35 927 22 243 1,263 20,000 Lower Hutt 96 48 243 29,685 148 811 93 1,770 6,441 39,335 Masterton 483 268 14 59 9,117 14 226 108 111 10,399 Porirua 33 62 587 1,121 49 12,636 28 474 4,153 19,143 South Wairarapa 441 37 24 76 778 18 1,785 139 106 3,403 Upper Hutt 212 29 126 2,046 338 404 205 10,206 1,396 14,962 Wellington 72 64 483 5,549 136 3,070 82 841 80,687 90,983 Grand Total 2,965 1,736 18,502 39,152 11,821 17,997 2,716 13,877 94,357 203,123 AM % Difference 2006 - 2026 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South Hutt Upper Wellington Total Grand Carterton 16% -2% 69% 47% 17% 47% 11% 50% 26% 17% External 3% 0% 22% 45% 24% 23% -4% 36% -2% 21% Kapiti 100% 28% 29% 61% 117% 40% 60% 63% 19% 30% Lower Hutt 61% 37% 28% 17% 74% 0% 47% 21% 6% 15% Masterton 14% 14% 91% 91% 13% 105% 34% 85% 55% 15% Porirua 60% 12% 17% 8% 74% 24% 41% 14% 9% 19% South Wairarapa 6% 9% 37% 3% 35% -9% 21% 16% -5% 20% Upper Hutt 66% 14% 7% 11% 77% -5% 48% 20% -6% 16% Wellington 60% 26% 21% 30% 68% 28% 32% 22% 28% 28% Grand Total 19% 23% 28% 19% 17% 23% 24% 21% 24% 23% May 2011 Issue 2 14 Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis Table 4-2 : IP Change in Vehicle Trip Distribution 2006-2026 IP 2006 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South Hutt Upper Wellington Total Grand Carterton 1,247 25 4 26 549 8 305 56 29 2,249 External 27 - 785 27 224 47 11 14 46 1,180 Kapiti 4 783 13,593 180 5 484 7 111 441 15,605 Lower Hutt 27 28 189 25,250 46 668 51 1,347 3,309 30,916 Masterton 554 209 7 45 8,340 13 339 109 66 9,682 Porirua 8 46 535 669 13 10,697 13 327 1,933 14,242 South Wairarapa 307 11 8 50 337 13 1,504 112 49 2,391 Upper Hutt 57 15 118 1,341 107 333 111 9,035 687 11,804 Wellington 30 47 420 3,293 70 1,860 49 641 60,130 66,539 Grand Total 2,261 1,164 15,658 30,882 9,691 14,122 2,388 11,751 66,691 154,607 IP 2026 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South Hutt Upper Wellington Total Grand Carterton 1,480 26 9 51 651 17 337 105 50 2,725 External 28 - 991 42 279 60 11 18 56 1,482 Kapiti 7 987 17,696 229 13 527 10 122 499 20,088 Lower Hutt 53 43 243 29,351 108 726 81 1,566 3,894 36,064 Masterton 659 251 15 108 9,507 34 430 240 120 11,363 Porirua 18 57 613 734 34 13,046 21 360 2,329 17,212 South Wairarapa 337 10 12 80 425 21 1,838 179 70 2,972 Upper Hutt 105 19 132 1,558 232 364 175 10,746 729 14,059 Wellington 53 60 479 4,041 126 2,279 73 705 75,736 83,552 Grand Total 2,740 1,451 20,190 36,193 11,374 17,073 2,976 14,041 83,480 189,518 IP % Difference 2006 - 2026 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South Hutt Upper Wellington Total Grand Carterton 19% 1% 103% 97% 19% 113% 11% 87% 72% 21% External 4% 0% 26% 54% 25% 28% -3% 30% 20% 26% Kapiti 111% 26% 30% 28% 148% 9% 52% 10% 13% 29% Lower Hutt 96% 52% 28% 16% 133% 9% 61% 16% 18% 17% Masterton 19% 20% 130% 138% 14% 165% 27% 120% 80% 17% Porirua 113% 23% 15% 10% 160% 22% 68% 10% 20% 21% South Wairarapa 10% -5% 52% 61% 26% 65% 22% 60% 42% 24% Upper Hutt 83% 28% 12% 16% 116% 9% 58% 19% 6% 19% Wellington 77% 28% 14% 23% 81% 23% 49% 10% 26% 26% Grand Total 21% 25% 29% 17% 17% 21% 25% 19% 25% 23% May 2011 Issue 2 15 Hutt Valley – Porirua Link Option Assessment Wellington Transport Strategy Model Analysis Table 4-3: PM Change in Vehicle Trip Distribution 2006-2026 PM 2006 Row Labels Carterton External Kapiti Hutt Lower Masterton Porirua Wairarapa South Hutt Upper Wellington Total Grand Carterton 1,610 39 8 52 518 16 400 113 37 2,793 External 39 - 1,058 35 248 60 27 26 49 1,540 Kapiti 3 1,111 15,770 213 4 629 8 153 547 18,438 Lower Hutt 28 48 297 30,584 41 999 60 1,843 4,846 38,746 Masterton 747 328 11 82 9,767 24 584 195 79 11,818 Porirua 8 81 693 849 11 12,954 16 454 2,838 17,904 South Wairarapa 287 13 9 62 268 18 1,819 145 51 2,673 Upper Hutt 54 27 161 1,646 89 450 116 10,930 932 14,406 Wellington 33 123 953 6,064 69 3,625 70 1,435 73,440 85,812 Grand Total 2,809 1,771 18,960 39,589 11,015 18,775 3,100