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Abstract

This paper reviews the incentive structure of concession contracts in several Latin American transit reforms. It also presents a conceptual analysis of the optimal design of concession contracts. The conceptual discussion and case studies reviewed indicate that payment to operators should be linked to operational variables and that some demand risk should optimally be transferred to operators. Performance standards linked to fines and penalties are not sufficient to guarantee good quality of service, particularly in citywide reforms and where institutional capacity ― in terms of size, experience and expertise of staff ― is lacking and regulatory processes are slow, bureaucratic and cumbersome. This review may be useful for policy-makers designing transit reforms in other countries. The policy lessons of the paper are particularly relevant to cities in the developing world but they are also important for reforms in other countries.  相似文献   
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Dune systems are essential to the ecological balance and sediment inputs of coastal environments and they provide numerous environmental services; however, their existence is threatened by natural and human stressors that contribute to their degradation. Future impacts are expected to be greater because of global climate change in association with further rises in sea level. Beaches and dune systems occupy large areas along the coastline of the state of Veracruz on the Gulf of Mexico. The aim of this study is to establish the intrinsic vulnerability of nine dune fields in Veracruz to current and future impacts and to assess their integrated management status. These dune–beach systems are more vulnerable to the effects of economic activities and land use change than to those induced by natural forces. Results show that six of these dune systems have medium vulnerability and an ecological conservation policy should be adopted; the other three, with high or very high vulnerability, are candidates for a restoration policy.  相似文献   
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Montecinos  Julio  Ouhimmou  Mustapha  Chauhan  Satyaveer  Paquet  Marc  Gharbi  Ali 《Transportation》2021,48(5):2401-2431
Transportation - A sharing logistics platform for less-than-truckloads could increase efficiency in city pickup and last-mile deliveries under time window constraints by pairing (matching) truck...  相似文献   
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