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Safety investments and operating conditions: determinants of accident passenger-vessel damage cost.

I. Introduction

Econometric transportation safety research heretofore has focused on the likelihood of the occurrence of "safety related events" (event probability), e.g., investigating determinants of accident rates.(1) However, the risk of travel to the passenger (i.e., the probability of sustaining injury or death) not only has the aspect of event probability but also the aspect of severity conditional probability - the severity of the event given that it has occurred.(2) Hence, an alternative (to event probability) for investigating the risk of travel is to focus on the severity of "safety related events." Since the severity of a "safety related event" is conditioned upon the occurrence of the event, the event and severity conditional probabilities of "safety related events" are expected to have common determinants.

Phillips and Talley [17] focus on the severity of air accidents and incidents by investigating determinants of their aircraft damage severity.(3) The study reports aircraft damage data as a discrete ranking, consisting of four classifications (no damage, minor damage, substantial damage and aircraft destroyed). This paper contributes to the econometric transportation safety literature by also focusing on the severity of "safety related events" and investigating determinants of this severity. It differs from Phillips and Talley [17] by: 1) measuring damage severity in damage cost (i.e., as a continuous unit of measurement), 2) providing estimates of accident marginal damage costs (with respect to given determinants), and 3) providing estimates of accident incremental damage risks (with respect to given determinants). Further, the paper investigates the severity of "safety related events" heretofore not addressed in the econometric transportation safety literature - commercial passenger-vessel accidents. Our investigation of the severity of these accidents is timely given the rising concern for the safety of commercial passenger-vessel service. Detailed data (provided by the Coast Guard) on individual commercial passenger-vessel accidents are utilized in our investigation.

The remainder of the paper is structured as follows: Section II presents a discussion of United States (U.S.) commercial passenger-vessel service and safety. Section III presents a model of accident passenger-vessel damage cost. Data are discussed in section IV. Tobit estimation results are detailed in section V, followed by a discussion of vessel damage cost and risk estimates in section VI. Conclusions are presented in section VII.

II. U.S. Commercial Passenger-Vessel Service and Safety

U.S. flag passenger vessels include sightseeing excursion, coastal overnight cruise, dinner cruise and ferry vessels and are classified by the Coast Guard into small and large vessel categories. The former are less than 100 gross tons in size and certified with: coastwise routes; ocean routes; lakes, bays, and sounds routes; and Great Lakes/river routes. Large passenger vessels are 100 or more gross tons in size; the majority are ferry vessels.

In 1988, approximately 5,000 U.S. and 81 foreign flag commercial passenger vessels operated from U.S. ports. Ferry vessels carried more than 50 million passengers; the remaining vessels carried an estimated 6.75 million passengers [12, 1 and 17]. In Seattle, ferry vessels range in size from approximately 500 to 3,200 gross tons and carry 18 million passengers annually; New York City ferries carry approximately 20 million passengers annually. More than half of the world's fleet of large foreign flag passenger vessels operate from Florida in the Bahamas, Caribbean, and cruise-to-nowhere trades and many fly so-called "flags of convenience" of Liberia, Panama and the Bahamas.(4) The ports of Miami and Fort Lauderdale are the world's largest and second largest cruise vessel ports, respectively [15]. Foreign flag passenger vessels operating from U.S. ports comprise between 80 to 85 percent of the world fleet measuring over 5,000 gross tons [12, 21].(5)

In 1991, approximately 4 million passengers boarded cruise vessels in U.S. ports; this number is expected to reach 7 to 10 million by the year 2000 [13, 1]. In 1990, 17 new or "substantially converted" passenger vessels entered the U.S. cruise market, followed by 7 new vessels in 1991 and 13 new vessels in 1992 [7, 3]. With the infusion of new vessels, the average age of vessels operating in the U.S. cruise trade has decreased, thereby increasing the overall safety level of the fleet, since new vessels are required to meet more stringent safety standards than older vessels.

In 1983, U.S. flag commercial passenger vessels operating in U.S. waters were involved in 216 accidents (of which 10 were total vessel losses); by 1989, the number had increased to 343 (of which 21 were total vessel losses). The 1983 accidents resulted in one fatality and 15 injuries; the 1989 accidents resulted in 8 fatalities and 44 injuries.(6) In 1983, none of the vessel accidents investigated by the National Transportation Safety Board (NTSB) involved a foreign flag commercial passenger vessel; in 1989, the NTSB investigated two foreign flag vessel accidents - one resulted in no fatalities and injuries, whereas the other resulted in 3 fatalities and one injury [13, 3]. The rising number of passenger-vessel accidents, fatalities and injuries along with the expected growth in passengers have generated concern for the safety of U.S. commercial passenger-vessel service.

The NTSB [12] study of the safety of commercial passenger vessels operating from U.S. ports expressed the following safety concerns: 1) insufficient licensing of crew and operators, 2) vessel instability and 3) insufficient fire protection. Roll-on roll-off ferry vessels have giant holes that allow for the loading (roll on) and the unloading (roll off) of automobiles and other cargoes. These giant holes preclude vertical watertight bulkheads that are standard features on most commercial vessels; if water gets in and causes a pronounced list, the vessel will capsize and sink [2]. If their loading doors are breached, they can sink without warning. Approximately sixty percent of roll-on roll-off ferry vessel accidents sink within ten minutes [2]. Ferry vessels are also subject to capsizing from pronounced lists caused by strong winds. Concern for the instability of ferries prompted the British Department of Transport in 1992 to submit proposals to the International Maritime Organization (IMO) for establishing tougher international standards to improve the stability of damaged ferries.(7)

In 1992, the IMO, in response to the 1989 NTSB study [12] and the urging of the Coast Guard, adopted SOLAS (Safety of Life at Sea) amendments that will significantly improve international passenger-vessel fire safety standards. These amendments (or standards) will be phased in over the period 1994 to 2010 and include: 1) requiring passenger vessels to carry additional fire-fighting equipment, 2) mandating improvements in the arrangements of fire doors and stairway enclosures on vessels to enhance fire escape, 3) requiring smoke detectors and automatic sprinkler systems on vessels that were previously not required to have them, and 4) expanding fire training for crew members.(8) Having discussed the safety of U.S. commercial passenger-vessel service, we now present a model for investigating the vessel damage severity of commercial passenger-vessel accidents.

III. A Model of Accident Passenger-Vessel Damage Cost

The vessel damage cost per (vessel) gross ton (VDCT)(9) of a commercial passenger-vessel accident is a function of carrier safety investments, operating conditions, and type of accident. Carrier safety investments consist of actions by passenger-vessel carriers (or lines) to improve the safety of vessel service. Such investments include utilizing experienced vessel operators, newer and larger vessels, vessels with stronger hull construction material, and vessels with safer propulsion sources (e.g., fuels). Operating conditions describe the environment in which a vessel was operating at the time of an accident. This environment includes phase of vessel operation, type of waterway utilized, and weather/visibility characteristics. Phillips and Talley [17] also expressed aircraft damage severity as a function of carrier (i.e., airline) safety investments and operating conditions, while Rose [18] expressed aircraft accidents as a function of airline safety investments and operating conditions. In addition, we investigate whether vessel damage cost varies by type of accident.

We measure the experience of a vessel's operator by the binary variable LICENSE - equaling one if the vessel at the time of the accident was manned by a licensed individual and zero if manned by an unlicensed individual. A more experienced operator is expected not only to reduce the risk of an accident but also to lessen the vessel damage given that an accident has occurred, e.g., a more experienced operator is more likely to be able to limit the damage of a disabled vessel. Vessel age (VAGE) is measured in years. A positive relationship is expected between VAGE and VDCT, since vessel structural failure is expected to increase with age.(10) Vessel size (VSIZE) is measured in gross tons. The a priori sign of the relationship between VSIZE and VDCT is indeterminate. Although larger vessels are expected to be more seaworthy (i.e., less susceptible to hazardous and windy weather), it is unclear once an accident occurs whether they will be susceptible to more or less damage than smaller vessels.

Our passenger vessels' hull construction materials are of three types: aluminum (ALUM), plastic (PLAS), i.e., fiber glass, or steel. Since steel is the strongest of these materials, we expect a vessel constructed with steel rather than aluminum or plastic to incur less damage in the same accident environment. The vessels' propulsion sources also are of three types: diesel (DIES), gasoline (GAS), or steam. It is unclear, however, which of these propulsion sources is safer and therefore expected to result in less accident vessel damage cost per gross ton.

We describe phase of vessel operation by whether the vessel was adrift (ADRIFT), underway (UNDERWAY), or docked or moored. The a priori signs of the relationships between ADRIFT (versus docked or moored) and VDCT and UNDERWAY (versus docked or moored) and VDCT are indeterminate. Although a vessel that is adrift or underway (versus docked or moored) is more likely to have an accident, it is unclear once an accident has occurred whether the vessel will incur greater accident damage than a docked or moored vessel (e.g., a docked or moored vessel involved in a fire accident). We describe type of waterway utilized as either a coastal (COAST), inland (INLAND), or ocean waterway. The expected signs of the relationships between these variables and accident vessel damage cost per gross ton are also indeterminate. Although a vessel is more likely to have an accident in the waterway where its service is concentrated, it is unclear whether this vessel will incur greater accident damage in this waterway.

Weather/visibility characteristics at the time of a vessel accident include precipitation (PRECIP) such as rain and snow, wind speed (WIND) and visibility. Although precipitation is likely to increase the risk of a vessel accident, its impact on the severity of an accident is unclear. A positive relationship is expected between WIND and VDCT. The tonnage-to-length ratio of passenger vessels relative to that of other commercial vessels makes passenger vessels relatively unstable, contributing to their capsizing from strong winds and/or the accumulation of water in hulls. Visibility is differentiated by time of day, i.e., by whether the accident occurred at night (NIGHT) versus day. Although poor visibility at night is expected to increase the risk of an accident, its impact on VDCT is unclear.

The extent of vessel damage cost is also expected to vary by type of accident. We classify the type of vessel accident as either a collision (COLLISION), a fire/explosion (FIRE-EXPLOS), a material/equipment failure (MAEQ-FAIL), or a grounding accident.(11) It is unclear which type of accident will result in greater VDCT. However, the concern expressed by the NTSB [12] for fire protection on passenger vessels may suggest that greater vessel damage cost is expected in fire/explosion accidents.

IV. Data

This study utilizes detailed data of individual U.S. flag commercial passenger-vessel accidents that occurred in U.S. waters for the nine year time period 1981-1989. Given the spareness of foreign flag vessel accidents in our data, we restrict vessel accidents to those of U.S. flag vessels. Further, given the spareness of accidents by larger passenger vessels in our data, we also restrict vessel accidents to those of small passenger vessels (less than 100 gross tons in size). In addition to those variables discussed above, we also utilize yearly time binary variables representing the years 1981-1989. Real VDCT was determined by dividing VDCT by the price index of vessel construction and repair (divided by 100). Variables and their specific measurements appear in Table I.

Data on individual passenger-vessel accidents were obtained from a computer tape of marine casualty information (i.e., the CASMAIN database) supplied by the Coast Guard. Data for the price index of vessel construction and repair were obtained from various issues of Producer Prices and Price Indexes [4]. Table I also reports descriptive statistics (mean and standard deviation) for the variables.

Accident vessel damage costs are costs (e.g., material and labor) to be incurred or incurred to restore damaged vessels to their service conditions which existed prior to their accidents. They are estimated or actual damage costs provided by owners (or their representatives) of damaged vessels to Coast Guard Investigating Officers and do not include the cost of salvage, gas freeing, cleaning, or drydocking. Damage cost estimates are considered to be accurate subject to verification by Investigating Officers.

V. Tobit Estimation Results

Given that vessel accidents do not necessarily result in vessel damage cost, the distribution of real VDCT are censored, i.e., some observations are zero. If a statistical technique such as ordinary [TABULAR DATA OMITTED] least squares that ignores censoring is utilized, the parameter estimates may be biased. Tobit analysis, which explicitly accounts for a censored dependent variable, eliminates this source of estimation bias.(12) Further, we reduce the chance of estimation bias from omission of relevant explanatory variables by including yearly time binary variables which control for the exclusion of other causal factors affecting accident vessel damage cost.

Results of the Tobit estimation of our vessel damage cost model appear in Table II.(13) Four carrier safety investment variables, LICENSE, VSIZE, ALUM, and PLAS, are statistically significant. The negative sign for LICENSE suggests that if a licensed operator is in command, the vessel damage cost per gross ton will be less. The coefficient of VSIZE is negative, suggesting that larger vessels incur less accident damage cost per gross ton than smaller vessels in a given accident environment. The parameter estimates of ALUM and PLAS suggest that damage is less if a vessel's hull is constructed with steel rather than aluminum or plastic, ceteris paribus.

Among operating condition variables, only WIND is significant. The positive sign of the coefficient of WIND provides support for the passenger-vessel instability safety concern relating to wind. Specifically, the positive sign suggests that accident passenger-vessel damage severity per gross ton is directly related to the wind speed at the time of the accident.

The estimation results further reveal that the coefficient for only one type-of-accident variable is significant. The coefficient of FIRE-EXPLOS is positive and significant, suggesting that fire/explosion accidents result in greater passenger-vessel damage per gross ton than other types of accidents - supporting the concern expressed by the NTSB [12] that greater passenger-vessel damage is expected in fire/explosion accidents. Further, the coefficient of FIRE-EXPLOS is several times greater than the coefficients of COLLISION and MAEQ-FAIL.

VI. Vessel Damage Cost and Risk Estimates

Tobit coefficients do not measure the correct regression coefficients for non-zero observations of the dependent variable. McDonald and Moffitt [8, 318-19] show that the total change in the dependent variable from a change in an explanatory variable, measured by the latter's Tobit coefficient, is the sum of two intuitive parts. With respect to our dependent variable VDCT, these two intuitive parts are: 1) the change in VDCT for those vessels incurring accident damage cost, weighted by the probability of a vessel accident incurring damage cost (i.e., accident vessel damage risk), plus (2) the change in accident vessel damage risk, weighted by the expected VDCT for those vessels incurring damage cost. The change in the dependent variable (for its observations above a limit such as zero) from a change in an explanatory variable can be measured as the product of the explanatory variable's Tobit coefficient and the adjustment factor "A":

A = {1 - [zf(z)/F(z)] - [f[(z).sup.2]/F[(z).sup.2]]}, (1)

where, z represents an evaluation of the Tobit equation divided by the equation's standard error; f(z) is the unit normal density; and F(z) is the cumulative normal distribution function. We refer [TABULAR DATA OMITTED] to products of "A" and Tobit coefficients as adjusted Tobit coefficients (reported in Table II) for interpreting the relationships between VDCT (for those vessel accidents that incur vessel damage cost) and the Tobit-equation explanatory variables.(14)

The adjusted Tobit coefficient (i.e., the accident marginal vessel damage cost) of vessel size suggests that an increase in vessel size (of vessels incurring accident damage cost) by one gross ton is expected to decrease accident vessel damage cost per gross ton by $2.35, other factors remaining the same. Other adjusted Tobit coefficients suggest that: licensed (versus unlicensed) manned operators are expected to reduce accident vessel damage cost per ton by $285.46; vessels constructed with aluminum and plastic (versus steel construction) are expected to increase vessel damage cost per ton by $243.38 and $369.89; an increase in wind speed by one knot is expected to increase vessel damage cost per ton by $9.23; and a fire/explosion accident (versus a grounding accident) is expected to increase vessel damage cost per ton by $736.36.

McDonald and Moffitt [8] also demonstrate that the change in the probability of the dependent variable being above a limit from a change in an explanatory variable can be expressed as the product of the explanatory variable's Tobit coefficient and the adjustment factor "B" :

B = f(z)/(standard error of the Tobit equation). (2)

For this study, the limit is zero accident vessel damage cost. Hence, the change in the probability of being above the limit represents a change in accident vessel damage risk. Our estimates of f(z) and the standard error of the Tobit equation yield a "B" value of 0.000427. We refer to products of "B" and Tobit coefficients as accident incremental vessel damage risks, measuring the changes in accident vessel damage risk from changes in the Tobit-equation explanatory variables.


The accident incremental vessel damage risk of FIRE-EXPLOS is 0.533, suggesting that a fire/explosion (versus a grounding) accident increases the accident vessel damage risk by 53.3 percent. Command by licensed (rather than unlicensed) operators decreases this risk by 20.7 percent. Construction with aluminum and plastic (rather than steel) increases accident vessel damage risk by 17.6 and 26.8 percent.(15)

VII. Conclusion

Econometric transportation safety research heretofore has focused on investigating determinants of the likelihood of the occurrence of "safety related events" (e.g., accidents). However, the risk of a passenger sustaining injury or death is also affected by the severity of the "safety related event." A methodology for investigating determinants of this severity is found in this paper and was applied to investigating determinants of the vessel damage severity of commercial passenger-vessel accidents (heretofore not addressed in the econometric transportation safety literature). Vessel damage severity has a continuous scale of measure (i.e., damage cost) and estimates of accident marginal vessel damage costs and incremental vessel damage risks (with respect to given determinants) were obtained. Passengers, insurance firms, transportation manufacturers and other transportation participants will find such estimates useful information in their decision-making processes (e.g., mode choice, pricing and manufacturing decisions). The methodology may be applied to any mode, where similar accident data are available.

The passenger-vessel damage severity findings suggest that accident passenger-vessel damage cost per vessel gross ton (where vessels are less than 100 gross tons in size) is less if the vessel is manned by a licensed operator and larger the vessel; the damage cost is greater if the vessel accident is a fire/explosion (versus a grounding) accident and greater the wind speed at the time of the accident (supporting practioners' concern for the instability of passenger vessels). Policy implications of these results for reducing the vessel damage severity (and related passenger injuries and fatalities) of passenger-vessel accidents are to: increase the utilization of licensed manned operators, adopt means (e.g., regulation and vessel design) for preventing fire/explosion accidents, and reduce vessel instability (caused by wind speed) by vessel design or other means.

1. A review of this research is found in Loeb, Talley and Zlatoper [6].

2. Moses and Savage [11, 171] also note the drawback of approaching safety from the perspective of event probability by stating that "even if we were to define safety as the probability that a trip would end in an accident, there still would be the problem that accidents vary in severity from minor damage-only incidents to major tragedies with loss of life."

3. Definitions of air accidents and incidents are found in Phillips and Talley [17].

4. No large U.S. flag passenger vessels operate in this trade.

5. Although foreign flag vessels are registered abroad, they may be owned by U.S. citizens or corporations. For example, vessels of Carnival Cruise Lines are foreign flag, but are owned by the U.S. Arison family. The rationale for not registering U.S. owned vessels in the U.S. (i.e., sheltering under a "flag of convenience") include: a) reducing crew expenses by not having to utilize higher-wage U.S. crew members, b) reducing tax and various other governmental fees and c) avoiding stricter U.S. regulations and laws [21]. "Foreign cruise ships are subject to rules that are less stringent and vigorously enforced than those imposed on U.S. flag vessels" [9, B1]. Specific safety concerns in the use of foreign flag cruise vessels in U.S. waters include the threat of fire and language problems of foreign crews that aggravate safety hazards (e.g., not understanding emergency orders during lifeboat drills). As cruise vessels get larger, evacuating them will get harder. "A fire aboard a ship is worse than a high-rise fire ..." [14, 3B]. "On foreign registered vessels, only the entertainers, cruise directors and front office staff usually are from the United States. The rest are foreigners who work up to 18 hours daily and have very few benefits that Americans would demand" [16, 1B].

6. These data are from Coast Guard annual reports of vessel casualties for the perspective years.

7. The IMO is the maritime safety agency of the United Nations that establishes international safety standards for vessels at sea of nations that are signatories to the SOLAS conventions which were held in 1929, 1948, 1960 and 1974. Since the IMO has no enforcement powers of its own, these vessel safety standards, however, are voluntary for each member nation. In 1989, the IMO adopted a joint U.S./Liberian resolution to advance international cooperation in maritime casualty investigations. A discussion of this resolution is found in Sobey [19].

8. Although there is a worldwide trend toward parity in commercial vessel safety standards, there are significant differences among nations in their enforcement of safety standards. "Disparities in enforcement do much more than economic damage - they serve to undermine the safety system ..." [5, 10C]. Worldwide classification societies (about 40 in number) that certify vessel safety have been accused of relaxing standards. In 1984, the cruise vessel, Sundancer, underwent an $85,000 inspection by the classification society, the American Bureau of Shipping. Shortly thereafter, it sank after running aground off the coast of British Columbia. Evidence suggest that a non-detected construction flaw in converting the ship from a ferry to a cruise vessel (rather than the grounding) was the cause of the sinking [1]. In the past, marine insurers have only required a vessel to hold a classification certificate as evidence that it is safe. Concern for the reliability of these certificates led London marine underwriters in December 1991 to begin their own inspections of vessels they considered a high safety risk.

9. Since vessels vary greatly in size, we adjust accident vessel damage cost for vessel size, measured in gross tons.

10. Meek, Brown and Fulford [10] conclude that a positive relationship exists between ship casualty rates and ship age for ships in general.

11. Vessel accidents may be classified into four categories: 1) groundings - vessel is in contact with the sea bottom or a bottom obstacle, struck object on the sea floor, or struck or touched the bottom; 2) collision - vessel struck or was struck by another vessel on the water surface, or struck a stationary object, not another ship (an allision); 3) fire and explosion - the fire and/or explosion is the initiating event reported, except where the first event is a hull/machinery failure leading to the fire/explosion; and 4) material and equipment (or structural-machinery-other) - hull/machinery damage, missing, and miscellaneous non-classified reasons (e.g., ships sunk due to either weather or break-up related to causes not covered by other casualty categories).

12. The Tobit model was introduced to econometrics by Tobin [20]. For further discussion of Tobit analysis, see McDonald and Moffitt [8].

13. The estimated coefficients of the yearly time binary variables, as a set, are not significantly different from zero and are not shown in Table II. The model was reestimated with a time trend variable; the estimated coefficients of the yearly time binary variables and the time trend variable, as a set, are also not significantly different from zero.

14. Following McDonald and Moffitt [8], we obtain an estimate of z by evaluating the estimated Tobit equation at the mean values of its explanatory variables and then dividing this evaluation by an estimate of the equation's standard error. The estimated z is then used to obtain f(z) from a normal distribution table. Following McDonald and Moffitt [8, 319], we estimate F(z) by the fraction of our sample above the zero limit - i.e., the fraction of the vessel accidents in our data set for which them were damage costs - rather than obtaining F(z) from a cumulative normal distribution table. This fraction is 0.70; the calculated "A" value is 0.59.

15. "In a sense, Tobit combines regression and Probit frameworks" [3, 620]. We also estimated a probit model, utilizing the dichotomous classification - the vessel accident incurs damage cost versus no damage cost - and the explanatory variables appearing in the Tobit model. The estimated incremental vessel damage risks calculated from the Probit estimation are similar to those found from the Tobit estimation and therefore are not reported in this paper.


1. Abrams, Alan, "Cruise Ship Case Raises Doubts About Vessel Inspection Process." Journal of Commerce, 8 July 1992, 1A and 3A.

2. Barnard, Bruce, "Ferry Loss Raises Questions: Concept of Roll-On Vessels Faces Spotlight Again." Journal of Commerce, l0 March 1987, 16A.

3. Berndt, Ernst R. The Practice of Econometrics: Classic and Contemporary. Reading, Massachusetts: Addision-Wesley Publishing Company, 1991, p. 620.

4. Bureau of Labor Statistics, U.S. Department of Labor. Producer Prices and Price Indexes. Washington, D.C.: U.S. Government Printing Office, various issues.

5. Gracey, James S., "Many Question Value of Drive for Vessel Safety Standards." Journal of Commerce, 20 May 1985, 10C.

6. Loeb, Peter D., Wayne K. Talley, and Thomas J. Zlatoper. Causes and Deterrents of Transportation Accidents: An Analysis by Mode. New York: Quorum Books, forthcoming.

7. Lloyd's List International, London: Lloyd's of London Press, Ltd., 1992, p. 3.

8. McDonald, John F. and Robert A. Moffitt, "The Uses of Tobit Analysis." The Review of Economics and Statistics, May 1980, 318-21.

9. McGinley, Laurie, "Safety of Most Cruise Ships is Assailed as Dubious at Best." Journal of Commerce, 10 October 1989, B1 and B12.

10. Meek, M., W. R. Brown and K. G. Fulford, "A Shipbuilder's View of Safety." Maritime Policy and Management, October-December 1985, 251-62.

11. Moses, Leon N. and lan Savage, "Aviation Deregulation and Safety: Theory and Evidence." Journal of Transport Economics and Policy, May 1990, 171-88.

12. National Transportation Safety Board. Passenger Vessels Operating From U.S. Ports. Washington, D.C.: U. S. Government Printing Office, 1989, pp. 1, 17, 21.

13. -----. Accidents Involving Foreign Passenger Ships Operating From U.S. Ports 1990-1991. Washington, D.C.: U. S. Government Printing Office, 1993, pp. 1, 3.

14. Nevins, Buddy, "Fire Fears Prompt Probe of Cruise Ship Safety." Journal of Commerce, 10 November 1988, 3B and 10B.

15. -----, "Passenger Ship Hazards Revealed." Journal of Commerces, 5 April 1989, 1B.

16. -----, "Tower of Babel Hurts Cruise Safety." Journal of Commerce, 5 April 1989, 1B.

17. Phillips, Richard A. and Wayne K. Talley, "Airline Safety Investments and Operating Conditions: Determinants of Aircraft Damage Severity." Southern Economic Journal, October 1992, 157-64.

18. Rose, Nancy L., "Profitability and Product Quality: Economic Determinants of Airline Safety Performance." Journal of Political Economy, October 1990, 944-64.

19. Sobey, Michael J., "International Cooperation in Maritime Casualty Investigations: An Analysis of IMO Resolution A.637 (16)." Maritime Policy and Management, January-March 1993, 3-29.

20. Tobin, James, "Estimation of Relationships for Limited Dependent Variables." Econometrica, January 1958, 24-36.

21. Unsworth, Edwin, "Many Fear Ship Industry is Courting Disaster." Journal of Commerce, 3 March 1989, 1A and 10B.
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Author:Talley, Wayne K.
Publication:Southern Economic Journal
Date:Jan 1, 1995
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