Sains Malaysiana 29: 81-92 (2000)                                                                                                  Pengajian Kuantitatif/

Quantitative Studies

MA Problem in Assessing the Effectiveness

Kamarulzaman Ibrahim

School of Mathematical Sciences

Faculty of Science and Technology

Universiti Kebangsaan Malaysia 43600 UKM Bangi

Selangor D.E., Malaysia

ABSTRACT

In this study, a generalised linear modelling technique is applied to the number of accidents and traffic flow (total flow into the roundabout) for several small roundabouts in Newcastle upon Tyne for the years 1974 to 1992. There is a multicollinearity problem since there exists a high correla­tion between traffic flow variable and time variable as there has been an increase in traffic flow over time. Traffic flow is an important explanatory variable and cannot be dropped from the model. The conclusion regarding the effectiveness of small roundabouts over time can only be made under a weak assumption of accidents are proportional to flow. Based on this assumption, there appears to be no evidence of the reduction of the effective­ness of the small roundabouts over time.

ABSTRAK

Dalam kajian ini, teknik pemodelan linear teritlak digunakan terhadap data kemalangan dan data aliran trafik dari tahun 1974 hingga tahun 1992 untuk beberapa bulatan kecil di Newcastle upon Tyne. Oleh kerana terdapat korelasi yang tinggi di antara pemboleh ubah masa dengan aliran trafik disebabkan bilangan trafik bertambah mengikut masa, terdapat satu masalah multikolinearan. Aliran trafik ialah satu pemboleh ubah penerang yang penting dan tidak dapat digugurkan daripada model. Kesimpulan tentang keberkesanan bulatan kecil terhadap masa hanya boleh dibuat berdasarkan satu andaian yang lemah, iaitu kemalangan berkadaran dengan aliran trafik. Berdasarkan andaian ini, tidak terdapat bukti bahawa keberkesanan bulatan kecil ini berkurangan terhadap masa.

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