Research Article

Practical Minimum Sample Size for Road Crash Time-Series Prediction Models

Table 1

Summary of literature related to sample size, models, and results.

ReferenceSample size/periodMethod/locationFindings

Adebola et al. [3]51 years (1960–2013)ARIMA model, NigeriaRoad injury and fatal crashes will increase in the following 7 years; however, the models should be used with caution for predicting future conditions beyond the forecasted period
Atubi, 2013 [4]32 years (1970–2001)Time-series analysis, NigeriaRoad traffic accidents were generally on the decrease
Mutangi, 2015 [5]17 years (1997–2013)ARIMA model, ZimbabweForecasting of the number of road traffic crashes using a white noise process is difficult because the values at different times are statistically independent
Avuglah et al. [6]20 years (1991–2011)ARIMA model, GhanaThe trends and patterns of road crashes were studied, and a five-year prediction was made. The study showed an increasing trend for the coming five years.
Parvareh et al. [7]72 months (2009–2015)ARIMA model, Kurdistan Province, IranInjury crashes for the following 24 months were predicted. Motorcyclists and pedestrian injuries showed a seasonal pattern. Results showed an increasing trend in the frequency of nonfatal injuries and a decline in fatalities.
Zolala et al. [8]36 months (2013–2015)SARIMA model, Kermanshah Province, IranTraffic fatalities showed a decreasing trend in the following years
Yousefzadeh-Chabok et al. [9]84 months (2007–2013)ARIMA model, Zanjan Province, IranThey found similar results to Zolala et al., 2016 [8]
Yuan et al., 2013 [10]60 years (1951–2011)ARIMA model, ChinaRoad traffic crashes would be increasing in year 2012
Rohayu et al. [11]40 years (1972–2010)ARIMA model, MalaysiaThey predicted road fatalities for the following five years (2015 and 2020)
Al-Ghamdi, 1995 [12]11 years (1980–1991)ARIMA model, Saudi ArabiaAn increase in the studied types of crashes was revealed
Al-Zyood, 2017 [13]18 years (1998–2016)ARIMA model, Saudi ArabiaCar crashes, injuries, and fatalities were forecasted for the following 7 years; all will be increasing
Al-Omari et al. [14]13 years (1998–2010)Multiple-linear regression and logarithmic models, JordanTraffic crash frequencies and fatalities in terms of motorization level were modeled; traffic crashes were continuously increasing
Jadaan et al. [15]10 years (2000–2009)Multiple-linear regression, JordanFatalities were correlated with population, number of registered vehicles, and total length of paved roads; the crash cost will be increasing
Ljubič et al. [16]21 years (1979–1999)Simple statistical visualization and graphic presentation, UKA clustering approach was used to find trends of road crashes through different time segments
Colum, 2018 [17]Weekly data (2005–2014)ARIMA model, UKCrashes, casualties, and vehicles were modeled. The models are useful in making future predictions.
Tang et al. [18]8 years (2005–2012)Negative binomial (NB) and random parameters negative binomial (RPNB), USAThe RPNB model provides better predictions when applied to within-sample observations, while the NB model provides better predictions when applied to out-of-sample observations
Liu and Sharma, 2017 [19]10 years (2006–2015)Integrated nested Laplace approximation (INLA) to estimate Bayesian spatiotemporal models, USASpatial and temporal correlations are critical in crash frequency modeling; the vehicle-miles-traveled was the only significant variable. Fatal crashes showed decreasing trends
Russo et al. [21]5 years (2006–2010)Negative binomial regression, ItalyThe AADT, lane width, curvature change rate, length, and vertical grade are important variables in explaining the severity of crashes. The HSM overestimates the crash frequency for rural undivided roads.